venv fix, version checking and test fix

[cmccarthy1]

• Addition of check in place to see if user is in a virtual environment across p.q, py.h and py.c this fixes #43
  1. Check comparison of sys.prefix with sys.base_prefix
  2. Passes equality check to init and chooses Py_SetPythonHome/Py_SetProgramName for non-venv/venv respectively prior to init
• Removal of p.so from *64/ folder on execution of make clean
• Check for gcc version >=5 to account for compilation errors in for gcc<5
• Modifications to ci tests to fix issues with incomplete execution for travis conda builds and appveyor builds
• Modification to tensorflow function definition to account for user functionality update