UI progress & changes

ButtonBar split into PaintBar and LayerManagementBar
ColourPicker, PaintBar, LayerMgmtBar and PaintPanel now listenable
ColourPicker: spinner, slider, and colour preview now in sync
lowered border for colour preview
layer-list now scrollable
tools-area now manually resizable
min size, pref size, insets, formatting, zoom fix
+Map.getLayerNames() & change HashMap to Linked~
private constructors for utility classes
Listeners for (almost) everyone! Also, events.