Shared resources are not located if chirp is installed to a virtualenv. Platform.executable_path() is searched for shared resources but, in a virtualenv, this returns the site-packages directory. The shared resources are located in (venv root)/share, which is a not a child of the site-packages directory.

This patch searches sys.prefix for data_files for compatibility with virtualenv installations and consolidates some of the resource-finding logic.

Thanks, Tim