Porthole pull requests merged

I merged all the pull requests from the main porthole product becsue
there hasn't been anything merged in over a year and a half
(https://github.com/ternarylabs/porthole/pulls)

*A more reliable way to check for browser support for postMessage. -->
https://github.com/ternarylabs/porthole/pull/10
*Native window.postMessage for IE8 -->
https://github.com/ternarylabs/porthole/pull/11
*ADD ability for receiver only legacyWindows -->
https://github.com/ternarylabs/porthole/pull/20
* Fixed detection of targetWindow inside iFrames -->
https://github.com/ternarylabs/porthole/pull/17
*Mootools Class collision fix. IE7-8 fix -->
https://github.com/ternarylabs/porthole/pull/26
*Others --> debug variable for silencing Porthole.trace in production;
strict type checks for null and empty strings; prefer window.console
object syntax