Merge pull request #4 from adscib/master

Sample script added.
Adding state mutating methods to World, gameover bug fixed.
Ruletris v0.2 - moveDown(), getX/Yoffset added, bugs fixed - GAME OVER, counters and others
Merging Ollie's work
Fixing few bugs
Even less bugs
Single line push roll-back
Single line push now works properly, but is not visualized properly.
Singl line push works, but not visualized properly
Always dropping a whole piece bug now fixed. NOTE: the piece is still put in offset 4 0 but not painted, if moved and successfully dropped game continues, otherwise GAME OVER.
Level objectives update
Update level_1.txt for objectives update
Merge pull request #6 from munraj/master

Level objectives update for tutorial system
Removed testing stuff
Fixed a comment
Merge pull request #8 from munraj/patch-2

Fixed a comment
Merge pull request #7 from munraj/patch-1

Removed testing stuff