Ghostscript on windows

[patstew]

Ghostscript is available in conda-forge, but camelot won't use it. I suggest adding a dependency to the conda-forge package, and make the code in _gsprint.py look on the path before hunting in the registry. I've installed it manually, and changed the code to:

    #libgs = __win32_finddll()
    libgs = "gsdll64.dll"

as a quick hack.

[vinayak-mehta]

Can you please try and see if this fix works for you? camelot-dev/camelot#32

You can install master to test it out.