the original layout is actually more space efficient if using CardFrame
instead of CardInfoWidget and reducing the size of the deck editor
toolbar.
this commit also removes the old search feature by removing the search
button and the clear search button. the clear search menu item is left
in place, however it now clears the filtertree.
finally, the stretch factor for the right frame in the main layout was
reduced to zero so that the card database gets priority for extra space.
this makes more sense because the deck editor does not actually need
very much horizontal space.
This is @mcallahan's patch — see #35. I had to apply this diff by hand,
because both `git` and `patch` refused to apply it and I didn't know
how to resolve that. Consequently, there might be an error.
filter builder takes filter options from user, then adds
completed filters to the filter tree. the filter tree does
not currently do anything. in the future it will filter the
cards in the database view.
