Added basic sprite creation to Fruit.

makeTestSprite(int color) can now be used to create a basic looking
sprite for any Fruit object. Each of the subclasses of Fruit now include
a call in the contructor.

Signed-off-by: Alex Colson <guythundar@gmail.com>
Added Grid Class.

Grid is the drawable contianer for each Fruit piece in the game as well
as the logic container. Most of the serious game logic will take place on
the Grid.

Signed-off-by: Alex Colson <guythundar@gmail.com>
Added Assets Class, Added new PRNG, Updated Rg

Assets, such as sprite art and music, will have a static wrapper found in
Assets.java and can therefore be referenced in the form Assets.* from
any source file.

Added a Mersenne Twister implementation to replace builtin Java PRNG.
This class was taken as part of an open-source class from
<http://www.cs.gmu.edu/~sean/research/mersenne/> under the MIT
License. Credits will added to a future Contributers/Thanks file. A static
instance of this PRNG can be found in Rg under the name rng.

Signed-off-by: Alex Colson <guythundar@gmail.com>