Added pictures for the pieces. Makes it
possible to change which piece is rendered
in each position. At the moment each
position is a white bishop for testing
purposes. Also changed the size of the
board so that you actually see the pieces.
Changed the margin to zero.
Merge pull request #8 from samni698/pieces

Ser bra ut, vackra bilder ^_^
Made Piece an abstract class. Added a
Board class to the engine which sets the
initial board positions in its
constructor.
Merge pull request #9 from samni698/engineStructure

Engine structure enhancements
Fixes a bug in the last commit.