Add full parsing of program pages

This commit introduces two options to the user:
* Only show episodes in program listing, but fallback to clips if no episodes are available.
* Or, group clips and episodes into two different sub-categories

The user can toggle the behavior in the add-on settings.

Without this commit, shows that have now episodes (but clips) will crash the script.
Merge pull request #50 from linqcan/newgetprogram

Add full parsing to program pages