Remove live() dependency in jquery.duplicate.js

The click handler is now attached directly to the DOM and is delegated
to `addButton`.

I've also added protection against an infinite loop where the plugin
attempts to indefinitely add items until `minItems` is satisfied.
Merge branch 'master' of github.com:vanillaforums/Garden

# By Dane MacMillan (1) and Todd Burry (1)
# Via Dane MacMillan
* 'master' of github.com:vanillaforums/Garden:
  Facebook social plugin: modified help text.
  Update the twitter plugin's endpoints to https.