Fix issues related to embedding multiple browsers in tabs

[GoogleCodeExporter]

There are many issues in CEF when embedding multiple browsers in tabs. It seems 
that it is always the first browser created to react when calling methods on 
the different frame objects. This includes methods like LoadUrl(), 
LoadString(), ExecuteJavascript(). Both browser1.frame.loadUrl() and 
browser2.frame.loadUrl() cause loading of an url in the first browser.

The fix to these issues might be to instantiate a separate client handler for 
each browser, instead of using one global handler, this was suggested as a 
solution in this topic by thile:
http://www.magpcss.org/ceforum/viewtopic.php?p=18212#p18212

Original issue reported on code.google.com by czarek.t...@gmail.com on 13 Dec 2013 at 5:30