* remove obsolete helper functions and make _state a public member.
* remove function assertions
* revert worker() changes
* Update pytest from 3.4.2 to 3.5.0
* Adapt exchange functions to ccxt API
Remove get_market_summaries and get_wallet_health, add exception handling
* Add NetworkException
* Change pair format in constants.py
* Add tests for exchange functions that comply with ccxt
* Remove bittrex tests
* Remove Bittrex and Interface classes
* Add retrier decorator
* Remove cache from get_ticker
* Remove unused and duplicate imports
* Add keyword arguments for get_fee
* Implement 'get_pair_detail_url'
* Change get_ticker_history format to ccxt format
* Fix exchange urls dict, don't need to initialize exchanges
* Add "Using Exchange ..." logging line
* telegram refactor 1/
move out freqcode from telegram
* telegram refactor 2/
move out rpc_trade_status
* telegram refactor 3/
move out rpc_daily_profit
* telegram refactor /4
move out rpc_trade_statistics
* 5/
* rpc refactor 6/
* rpc refactor 7/
* rpc refactor 8/
* rpc refactor 9/
* rpc refactor 10/
cleanups
two tests are broken
* fiat
* rpc: Add back fiat singleton usage
* test: rpc_trade_statistics
Test that rpc_trade_statistics can handle trades that lacks
trade.open_rate (it is set to None)
* test: rpc_forcesell
Also some cleanups
* test: telegram.py::init
* test: telegram test_cleanup and test_status
* test rcp cleanup
* autopep fixes
* remove unused imports
* fix plot_dataframe.py lint warnings
* make pep8 error fails the build
* two more line breakings
* matplotlib.use() must be called before pyplot import
