Add keyboard shortcuts for list menu option "filter"

git-svn-id: svn://svn.code.sf.net/p/autowikibrowser/code/AWB@10501 5227b50d-9349-4574-b055-4b0a7525e11c
Fix enablement of sort reverse alpha to match sort alpha in list maker context menu

git-svn-id: svn://svn.code.sf.net/p/autowikibrowser/code/AWB@10502 5227b50d-9349-4574-b055-4b0a7525e11c
Only enable clear list / convert to talk / convert from talk / save list menu options when list maker has one or more articles in it

git-svn-id: svn://svn.code.sf.net/p/autowikibrowser/code/AWB@10503 5227b50d-9349-4574-b055-4b0a7525e11c