deleted useless stuff
Changes gamelayer

1. Added boundary limit
2. Drew boundary box
3. Changed world tree position
Removed unittype constant
Bug fix

Fixed a bug in which somehow "whiteball.png" was not added to the
compilation when it was built for distribution.
Added new features

1. Line block placer
2. Restricted valid area
3. Created a method to unSelect
Change the colour of the blocks

Made it more visible