Fix bug that prevented passing list of strings as options to compass.
Fix bug that prevented passing list of strings as options to compass.

This was needed to pass the configuration param additional_import_paths through to compass.
Before this change, it would create a configuration file that looked like this:

additional_import_paths = "['/path/to/sass']"

Now it creates

additional_import_paths = ['/path/to/sass']

0x1997/webassets,heynemann/webassets,florianjacob/webassets,john2x/webassets,glorpen/webassets,scorphus/webassets,scorphus/webassets,heynemann/webassets,JDeuce/webassets,glorpen/webassets,florianjacob/webassets,aconrad/webassets,aconrad/webassets,0x1997/webassets,glorpen/webassets,JDeuce/webassets,wijerasa/webassets,wijerasa/webassets,john2x/webassets,aconrad/webassets,heynemann/webassets