Descendant searching

[mitchcapper]

As implemented in my PR the ability to quickly find a descendant based on one of many fields is quite useful. textbox for search text, combo for what field to search, enter to search, buttons up down to go to next / previous entry (next button also serves to search). Arrow keys up and down also search next/previous. Only searches current depth and lower. Shows what # of result you are on (and once you have found all the total # but doesnt calculate total ahead of time for perf).

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