Get paranoid about parsing aired date.
More date consistency and added yesterday properties.

Make the per-day and today properties match what is being put into the
episode NextDate/LatestDate fields.  Add YesterdayDate property as well
as localized names for Today and Yesterday (allowing a skin to string-
substitute Yesterday and Today strings in place of those dates).
Make the Weekday values set consistently.

Now that we have the localized Yesterday and Today values as their own
properties, we can set the *.Weekday properties to their names w/o any
exceptions (allowing the skin to choose how they want to display the
info).
Don't try to use buggy tzwin support.