Issue 6514: Look in closures when getting return values of "new A()" for auto-completion

http://code.google.com/p/fbug/issues/detail?id=6514
FBTest for issue 4156 (Multiple filters selectable in Net panel)
http://code.google.com/p/fbug/issues/detail?id=4156
FBTest: additional tracing to figure out random failures
Merge branch 'master' of github.com:firebug/firebug
Merge branch 'master' of github.com:firebug/firebug into jsd2