Fixing a few issues

-Firefox: Fix OpenForge bug that prevents Firefox extension from running background JS
-Fixing main.py to get correct executing script path on windows
-Fix OpenForge defect that prevents the extension icon from showing in IE9 and above
-Extension icon does not show if creating a new IE window (Ctrl+N)
-Browser crashes if clicking on extension icon after closing a previously opened IE window
-IE8: Extension's popup up window remains open
-Updating IE VS projects to VS2012
-Updating .gitignore