Addition of virtualenv support

Addition of support for virtual environments (#103)

* venv support (#99)

* virtual env

* removed setting of python home

* cleaned up p.q

* working version for working environments

* update base prefix

* addition of py_SetProgramName

* added travis virtualenv

* added tests for sys commands. Added warning for windows virtual environment users

* fix windows venv warning

Co-authored-by: Dianeod <[email protected]>
Co-authored-by: Diane ODonoghue <[email protected]>

* Venv (#102)

* virtual env

* removed setting of python home

* cleaned up p.q

* working version for working environments

* update base prefix

* addition of py_SetProgramName

* added travis virtualenv

* added tests for sys commands. Added warning for windows virtual environment users

* fix windows venv warning

* Fixed stdOut issue (#101)

* Optional error message conforming to Python return. KXI-1467 (#100)

* Update to p.q logic for handling sys.argv

* reintroduction of old logic

* addition of initial sys argv and embedpy version check

* Addition of functionality to return Python traceback rather than q shorthand

* Memory leak fix and removal of environment variable check C side

* reformat of prr to use modifiable global rather than env variable

* Initial pass at rectifying potential buffer overflow

* update to py.c to initialize traceback import on init

* closer fit to code base style

Co-authored-by: Conor McCarthy <[email protected]>

Co-authored-by: cmccarthy1 <[email protected]>
Co-authored-by: Conor McCarthy <[email protected]>

* Explicit note that venv support limitation is only expected to hold for Windows

Co-authored-by: Dianeod <[email protected]>
Co-authored-by: Diane ODonoghue <[email protected]>
Co-authored-by: Conor McCarthy <[email protected]>