CONSTANTS
* STEEM_REVERSE_AUCTION_WINDOW_SECONDS_HF20 added

Nodelist
* nodes information updated

Steem
* get_dust_threshold() improved and get_config used
* hardfork checks improved
* hardfork property improved by using get_hardfork_properties function

Changelog.rst added and Issue #80 fixed

Make vote rshare calculations HF20 ready

adding methods to claim and create discounted accouts

Remove non appbase nodes and related tests from all unit tests Improve blockchain.stream() for appbase

Optimize sbd_to_rshares to not use an iterative approach

adding weku chain properties

Just a bunch of deleted whitespaces.

We can get rid of the iterative approach by utilizing a few formulars. This makes the function signature smaller as well as improving performance drastically while increasing the precision. 
I also added a few comments to make it more obvious what I'm doing here.

Some more unit tests

beembase/objects: fix serialization of appbase trx

Fix many documentation errors (based on error messages when building)

Refs #72

Added an example to the custom_json section for documentation.

Add get_vote_pct_for_SBD, sbd_to_vote_pct and sbd_to_rshares