preparing for issue 180 bugfix: create ZcToken Unit test suite

[robrobbins]

• actual bugfix is not the biggest issue here. There were no previous unit tests on the ZcToken as it was mostly a pass thru to existing tokens.
• much logic, and a found audit bug dictates that this contract now be setup for proper unit tests
• a new testing package is created with its accompanying setup
• one introductory spec -- the zctoken_construction_test is present to check that the token hydrates passed values correctly
• with this in place the actual spec for the the bugfix to issue 180 can be tested now
• that test is forthcoming