Metadata tweaks and updates

Metadata: ALL -- Minor cleanup, standardizations, remove unused variables. Removed namespace (was incorrect anyways)
Metadata: XBMC -- Strip leading/trailing spaces off Actor's names.
Metadata: TIVO -- Override 'non supported' functions to prevent erroneous metadata from being created.
Per Tivo docs, the value for rating can only be a whole number or a half..  round down to ensure that happens.
Metadata: MB -- Re-order and cleaned up the .xml generation to match what MB3 is generating. Note that for mult-ep they aggregate the episodes into the first ep (which we do now to match).