Add global_transform alias

Can now do

:global_transform

:global_transform = None

:global_transform = filter_read

etc.
Properly fail an int_range if fallback is also empty

item-list et. al. shouldn't ever receive an empty list.

This keeps c-c from dying when you, for example, try to execute :reader
without a selection.
Properly fail command chains when one fails
Make setup.py executable