Merge branch 'twitter-facebook-mods'

* twitter-facebook-mods:
  Make Facebook plugin look for API key and secret before doing anything
  Show global key and secret, if defined, in Twitter bridge admin panel
  Remove double word from Twitter bridge README
  - Have Twitter bridge check for a global key and secret if it can't
  stupid mistake... let's not talk about this.
  Updated some references to the long gnone "isEnclosure" function to the new "getEnclosure"
  Update Facebook plugin README with info about new admin panel
  Initial Facebook admin panel
  Some wording / spelling fixes
  - Make 'Sign in with Twitter' optional
  Remove un-needed config variable for enabling/disabling Twitter integration
  Initial Twitter bridge admin panel
  Upgrade XML output scrubbing to better deal with newline and a few other chars

diff --cc lib/action.php
Simple merge

diff --cc lib/apiaction.php
Simple merge

diff --cc lib/util.php
Simple merge