Merge branch 'release/0.1.11'

Makefile

bitshares/asset.py

bitshares/bitshares.py

bitshares/blockchain.py

bitshares/exceptions.py

bitshares/memo.py

bitshares/message.py

bitshares/transactionbuilder.py

bitshares/wallet.py

bitshares/witness.py

bitsharesbase/objects.py

bitsharesbase/operations.py

docs/index.rst

docs/memo.rst

requirements-test.txt

setup.py

tests/test_asset.py

tests/test_bitshares.py

tests/test_message.py

tests/test_transactions.py