- refactored attribute linked to slots through a mapped_to_slot_property (e.g. post_date <=> date-posted)
- refactor ISO currency code to use table of currencies instead of web
- reworked non_std_scu and commodity_scu code
- explicitly write __init__ of account to handle default values
- set commodity to Root Account when creating a book (specify mnemonic in create_book)
- validate transaction when flushing (check single currency transaction + add imbalance split if necessary)
- cleaning of unused/commented code
- fix some bugs
- fix tests
- remove requests as requirement
- porting to python 3
- fix Account.__init__ refactoring (commodity is mandatory, set to None if no commodity)
- porting to python3
- port to python3