Call JS_AddExtraGCRootsTracer and JS_RemoveExtraGCRootsTracer depending
on JS::Heap use instead of on CGUI page link setup.
GUIObjects should be able to access the GUI page independent of the
scripting (for example to obtain PredefinedColors, refs D2108).
Refs: D2108, c02a7e1a7b
Comments By: wraitii
This was SVN commit r22587.
The type differs from the Color type, because contrary to Color, it can
be created from a color predefined in the GUI page (such as "yellow").
Move this predefined color check to the new class instead of hardcoding
it in FromJSVal / ToJSVal, GUIUtil, JSInterface_IGUIObject and to
straighten the latter.
Delete fov_wedge_color from Minimap, unused since introduction in
5275dc862b.
This was SVN commit r22558.
