Creating a virtual enviroment with custom python version

[federicoB]

warpdrive project could take a -p flag for python version as virtualenv command

I tried to create a warpdrive project with an active virtualenv with custom python version.
If warpdrive is installed globally it's tries to access .warpdrive folder in home dir that doesn't exist.
If warpride is installed only in the virtualenv it tries to use os.py on line 24 of __init__.py but it's search os.py into the virtualenv. This cause an no such file error.