Make XXofYY work at top level of series.  Fixes #5.
Prefer (stronger) sXXeYY matches when filename also includes date.  Fixes #10.
Allow four-digit seasons (e.g. 2009x02).  Fixes #11.
Merge pull request #30 from plexinc-plugins/matching-tweaks

Fix some long-standing series scanner GHI's.