disable_chain_detection added to graphenerpc (for testing hivemind e.g.)

Transactionbuilder
* Prepare broadcasting in new appbase format
* Force condenser_api by now
RPCUtils
* Improve detection of conenser_api
Streemnoderpc
* Improved error message for Assert Exception:v.is_object()
beembase.Object
* Add new appbase Operation format
beemgraphenebase.object
* Add handling of new appbase operation format

Wallet
* getKeysForAccount added
* getOwnerKeysForAccount, getActiveKeysForAccount, getPostingKeysForAccount added
beemapi
* WorkingNodeMissing is raised when no working node could be found
GrapheneRPC
* cycle([urls]) is replaced by the nodes class
Nodes
* Node handling and management of url and error_counts is performed by the nodes class
* sleep_and_check_retries is moved to the nodes class
* Websocket, steemnodrpc were adpapted to the changes
Unit tests
* new tests for the nodes class
* tests adapted for websocket and rpcutils

Account
* print_info improved (Last Vote added)
* entryId changed to start_entry_id in get_feed, get_blog_entries and get_blog
*rpc.get_account_history moved to _get_account_history
* estimate_account_op added, can be used to fastly get account op numbers from dates or block nums
* history and history_reverse uses estimate_account_op
Exception
* KeyNotFound removed
Memo
* raises MissingKeyError instead of KeyNotFound
Price
* small improvement
Steem
* __repr__ added
Transactionbuilder
* get_potential_signatures, get_transaction_hex and get_required_signatures added
* raises MissingKeyError instead of KeyNotFound
VotesObject
* __contains__, __str__ and __repr__ added
Wallet
* raises MissingKeyError instead of KeyNotFound
Witness
* __contains__, __str__ and __repr__ added to WitnessObject
Steemnoderpc
* small improvements
Operationsid
* producer_reward 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

cli
* Add price prediction for buy and sell of cli
steemnoderpc
* refactoring
Exceptions
* CallRetriesReached added
unit tests
* tests for test_cli added

account
* set_withdraw_vesting_route added
cli
 * powerdownroute, convert and interest added
steemnoderpc
* error messages improved
* _check_api_name added
* ApiNotSupported when Api is not supported by node but exists
graphenerpc
* error messages improved
rpcutils
* error messages in sleep_and_check_retries improved
unit tests
* new function added

Graphenerpc
* some refafctoring
Steemnoderpc
* fix next_node_on_empty_reply

Steemnoderpc
* self.errror_cnt_call used instead of local variable doRetryCount
Graphenerpc
* num_retries_call added for setting a max number of retries on a rpc call
* self.n_urls added for getting the number of given nodes
* sleep on retry removed, when switching over to the next node
self.error_cnt_call used for counting rpc call retries
rpcutils
* sleep_and_check_retries improved
Unit tests
num_retries added
test_golos reduced

All rpc calls are handled with direct api call. Register api was a relict from bitshares.

* Wallet wipe improved
* wallet purge and purgeWallet renamed to wipe
* internal node error and Unable to acquire database lock handled
* login to websocket only if username and password is provided

Transactionbuild
* Automatic Signing with owner key removed
Beembase/account and beembase/bip38 removed as they are using beemgraphenebase/bip38 and beemgraphenebase/account

Block
* Block contains only the json data + id for block num
* Output for appbase and non-appbase is the same
Blockchain
* batch-rpc-calls added
Graphenerpc
* multithread for websocket activated
* batch with queue  added
Benchmark improved
Unit tests adapted

rpcutils.py added
Timestamp fixed for py27
New unit tests for test_rpcutils