Bitmerchant

Includes 51 - a potentially serious caching bug that could generate incorrect child wallets.

Thanks to shea256 for reporting the bug.

**All prior versions of `bitmerchant` are affected by this bug. Only use `bitmerchant>=0.1.8`**

**DO NOT USE** Contains a potentially serious bug (51)

Includes 49 - A fix for pip installing when not in a virtualenv.

**DO NOT USE** Contains a potentially serious bug (51)

This release contains several python compatibility fixes, making bitmerchant usable on python-2.5 through python-3.4, as well as pypy and pypy3. It also contains blockcypher.com testnet parameters.

Thanks to mflaxman and matthieu for the blockcypher parameters, and to benhc123 for the license date fix.

37 - Update the license date (benhc123)
38 - Fix an example in the readme (mflaxman)
43 - Add BlockCypher testnet parameters (mflaxman and matthieu)
45 - Compatibility fixes for all python versions >= python-2.5, and expanded test coverage for untested if branches