Integrity: Added new event 'error[name="config-mismatch"]'

 - [x] Integrity: Added new event 'error[name="config-mismatch"]'
 - [x] Security: Also added filtering to only honor FlashVars. Supersedes #336.
 - [x] Also revved version to 2.2.0-beta.3

Fixes #379
Fixes #164
Closes #336

Still don't have FlexUnit tests in place yet (:sob:), so I'm uncertain if this covers 100% of security holes previously identified in #164 and #336 by @masatokinugawa. However, I've also combined it with a new technique of using `ExternalInterface` to call out and interrogate the DOM for the actual FlashVars.

This DOM interrogation for FlashVars helps both with security (#164, #336) and in preventing weird browser caching issues for FlashVars (#379).

cc: @jonrohan @mjtko @nodesocket @masatokinugawa @ptoomey3 @jnewland @mastahyeti &rarr; _Please review!_

P.S. SWF size obviously increased again: 5.775 kb &rarr; 6.721 kb
**Update:** After 2nd commit, SWF size slightly reduced: 6.394 kb
I killed off `this.metadata` altogether to reduce SWF bloat, so it's no longer up for debate. :)