Work Progress - July 13 - Jul 19

Demo: "SB in beta" link above

* Core: In JPnlObjMgr, use ToolTipText to indicate the type of an object.
* SB: Fix the bug that all skateboarder objects share the same set of texture, even if we specify different looks for different skateboarders.
* Core: An additional basic property "z" is added for all PObjects. We can use that to control the drawing order of overlapping object. An object with a higher z number will appear on top of others with smaller z numbers.
* Make self-defined variables as a property of the object. An assignment statement can now take a variable or a property in its LHS.