Seperate config options from the configtree. VLCTreeItem and VLCTreeLeafItem
are now used for CONFIG_ITEM in an options collection. It now works, but
probably should be cleanup up a bit more, with better seperation between the
disjunct elements of Tree and ConfigItems.

This was broken since [09e31e1436ef3e670bd7497688272dd073c8d3a6]
(cherry picked from commit 1e7e2ae9)