Finishing!

Hello! This is your regular huge commit, along with its huge commit message.

- Philosophy change about the blocks: blocks can't be controlled, so they won't have a process dedicated to control them. All these ugly variables such as brick_broken_col and brick_broken_row have been dropped.
- Now ball won't overflow on the upper side or the lower side of the screen. Ball will also properly bump on the blocks when needed as the bricks have also been changed into totally 'solid' pieces of the game (not just its outline). Same applies to the bar.
- Now ball bumping into a brick will remove the brick and change the proper direction, thanks to the loops being now synchronous.
- When ball is not enabled (but anyways displayed on screen), it's been moved down for making the GAME OVER! text appear properly. 

Game has been reduced to 2x2 at the moment since the compiler eats up gazillions of memory and would be out of memory on setups bigger than than 2x3 bricks. Eats more than 2GB of physical memory!

Some unused and/or useless signals have been added in a desperate attempt to make it work properly. Don't worry, Xilinx WebPACK will take care of them, along with the variables that aren't on the sensitivity lists of each process.

Be warned though, I'm not fixing any of the warnings out there unless I feel like it since Xilinx WebPACK does it for you and you need Xilinx software to program the FPGA anyways.

For any other possible issue with the game, please fill out an issue at https://github.com/jaBote/Plong/issues or submit a pull request if you are knowledgeable of the language and syntax of VHDL since I'll be unable to fix most of them.

Compilation tests: PASS (@ Xilinx ISE 11.1)
Laboratory tests: PASS (@ tests on the live board)

Closes all currently open issues except documentation and to-do lists (even if they are already completed). Closes #16 as well.