[Changelog] python-steem 0.2.2

Release 0.2.2

New:

• [memo] allow decoding of 'sent' memos
• [rpc] add account_history call
• list_accounts generator added to SteemNodeRPC
• [api] allow streams with an array of operations
• [operations] add convert_operation

Fixes:

• [Makefile] Add Tags to changelog post
• [signing] removed redundante code to graphenelib
• [api] raise exception of no access to api instead of only posting an error
• Merge pull request #8 from noisy/PR-8-list_accounts
• Addressing CR comments
• [utf8] proper test case
• [tox] install development version of graphene libs for testing
• [transactions] fix python floating issue (https://github.com/xeroc/piston/issues/49)
• [transactions] utf-8 test
• [api] don't fail when try to obtain a nonexisting account but return None
• [transactions] correct prefix for verify() call
• [makefile] No more editing of old posts