Alpha field handling! Re-did a lot of the complexity after a chat session w/...

Alpha field handling!  Re-did a lot of the complexity after a chat session w/ bjaspan made it clear that having the bundle or type of media (for fielding purposes) determined dynamically was not going to work and making a new table would be a PITA - but can be done later.  Anyway, see the media.install for an extended description.  Fields works now! (kinda)