Two Separate trees: more independence for each

[DrShark]

From all Tree modes in TC I prefer this one, however I miss a possibity to move
tree-panel divider in this mode for each panel independently (currently
moving tree-panel divider in one panel moves it also in opposite), and even hide/close tree by
attaching it to left border of TC panel (in Vertical alignment of panels - for both trees) and center panel
divider (for right tree in Horisontal alignment of panels).
When I talk about "hide/close", I mean that visually it should be hiding in both cases
by attaching tree divider to a panel border/divider, but with "close" case TC should unload hidden tree
from RAM, so it shouldn't slow down a panel with hidden tree.