Added Fedora and Ubuntu to recognized OSes
Added new FBTest method checkIfContextMenuCommandExists() to check
whether an item is available within the context menu
FBTest for issue 5235 (Don't allow to inspect computed style in CSS
panel)
http://code.google.com/p/fbug/issues/detail?id=5235
FBTest for issue 4663 (Aborted requests show NaN MB in the size info
tip)
http://code.google.com/p/fbug/issues/detail?id=4663
Fix twisty appearance in FBTrace
Issue 7250: FBTrace doesn't display properties for inner object

https://code.google.com/p/fbug/issues/detail?id=7250
Merge branch 'jsd2' of github.com:firebug/firebug into issue7097
Tracing updated + clean up