[ENH] Provide file type filter to file browser, add search field

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53036 b456876b-0849-0410-b77d-98878d47e9d5
[ENH] Automatically focus the first field when opening modal dialogs

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53037 b456876b-0849-0410-b77d-98878d47e9d5