wls v2.5 reward / posting example

This reverts commit b86e513f.

* Improve file reading for beempy sign and broadcast
* add option to write file for beempy sign

* add claim_account RC calculation
* fix Bytes type
* Improve testnet example
* test_types improved

Example for using offline signing is provided
Next release prepared

Fix unit test

Snapshot
* update_in_vote added 
* enable_votes changed to enable_in_votes and enable_out_votes
* build_rep_arrays added
Example
* account_vp_over_time added
* account_reputation_by_SP added
Discussion
* check if parameter exists in discussion_query added

CLI
* upvote and downvote fixed
Snapshot
* refactoring
* update_vote and build_vp_arrays added for showing vote power history
Examples
* account_vp_over_time added

* get_data is now fast
* update_rewards added
* enable_rewards added to build
* build_curation_arrays added

Snapshot
* impoved and STEEM and SBD history added
* Documentation added
* get_data, reset, build functions added

Snapshot added
* This class can be used to access old account states. At the moment, only changes in vests are tracked over time.
* example added for plotting SP over time

Steem
* last_node added and refresh of json_config data is forced on node switch

Example
* A cache performance evalution script was added to examples
Blockchain
* set_cache_auto_clean disabled

* stream_threading_performance example added to evaluate threading
* _switch_to_next_node added to Steemnoderpc
* 5 tags restriction removed from post()

Blockchain
* Check if all block could be fetched added
* Thread and Worker class for block fetching added

Account
* lazy and full are correctly passed
* _parse_json_data() added to parse json
Block
* lazy and full are correctly passed
* empty operations are handled
* op_statistics improved
Blockchain
* virtual ops and ops statistics are seperatly calculated
Comment
* _parse_json_data() added to parse dates and amounts
* author_reputation is parsed to int
* lazy and full are correctly passed
Vote
* lazy and full are correctly passed
* _parse_json_data added to parse date and rshares and reputation
* vote.time is a datetime object
* json() returns the original string
Witness
* lazy and full are correctly passed
GrapheneRPC
* time_limit removed, as it supresses KeyboardInterrupt
* ws.settimeout() is set for websocket
* WebSocketTimeoutException  handling added
Unit tests
* test_account fixed
* test_time_limit removed from test_steemnoderpc
* checks added to test_blockchain_batch

* added use_stored_data to all steem function that uses constants e.g. get_config()
* Fix author for steem.post(), when a account object is entered
* **kwargs added to all broadcast function of steem
Account
* fix desribtion of update_account_profile
* added update_account_metadata

steem
* add steemconnect in init, when set, steemconnect is used for broadasting
steemconnect
* new class can be used to broadcast operation with steemconnect v2
storage
* Token class to store encrypted token
Transactionbuilder
* use steemconnect broadcast with set in steem
Wallet
* add token storage class
* add setToken, clear_local_token, encrypt_token, decrypt_token, addToken, getTokenForAccountName, removeTokenFromPublicName, getPublicNames
Example
* Add login app for testing steemconnect

NodeList
* replaces get_node_list from utils.py
* is a list and contains all nodes as dict
* get_nodes() returns the url in a list
Utils
* get_node_list removed
Unit Tests and Examples adapted to the changes

Account
* estimate_account_op renamed to estimate_virtual_op_num
Block
* only_ops and only_virtual_ops added as new parameter
* the transactions property returns a list of transactions
* The operations property returns a list of operations
* Block which contain only only_ops can be received now
Blockchain
* only_ops and only_virtual_ops added to get_current_block, blocks, wait_for_and_get_block and stream
* ops() is obsolete now
* stream uses now blocks internally
* only_ops=True streams now also virtual operaitons
cli
* autoconnect is the to False now and only when needed a  stm.rpc.rpcconnect() is performed
* ascii option added to all plots
* rewards added, this new command lists outstanding rewards (posts, comment and votes)
* curation added which shows the vote curation rewards for a single post
* verify added, which returns the public signing key of a transaction
Comment
* reward, is_pending, time_elapsed, curation_penalty_compensation_SBD, estimate_curation_SBD, curation_reward_pct, get_vote, get_beneficiaries_pct, get_rewards, get_author_rewards and get_curation_rewards added

Unit tests
* new function added and tests adapted to changes

Blockchainobject
* auto_clean function added. Everytime a new item is stored into the cache, all expired elements are removed.
* The __contains__ function sets now data ot None, when the date is expired, in order to reduce memory consumption
CLI
* threading for pingnode added. with --threading, all nodes are tested simultanously.
Steemnoderpc
* Error count and exception improved when only one node is available
Graphenerpc
* regests.session is stored as signelton
* requests_retry_session removed
* shared_session_instance and set_session_instance is used to get and set the global request.session object
* create_ws_instance added; A websocket is created everytime and the singleton is removed
* error_cnt and num_retries_call handling improved
RpcUtils
* sleep_and_check_retries improved
Examples
* benchmark_node2 uses threads (one thread for each node)
* memory_profiler2 added to check memory consumption for creating multiple account objects
Unit tests
* test for objectcache improved

Memo
* make prefix changeble
Transationbuilder
* sign() return the signed struct now
Graphenerpc
* Session are used for requests
* Singleton for websocket instance added
* Both measures reduce ram consumption when more than one Steem object is created.
Add missing scrypt package to dependency