First version of Tetris GUI - EXTREMELY useful to find bugs

* Wrap game inside Tetris object
* Catch user input to move and rotate pieces around
* Add all .js files in the correct order in order to run game
* Exclude main.js and Tetris.js from karma.conf.js
* Update Game HTML structure - remove canvas for now and use plain HTML objects
* Add simple styling in order to see things moving
Merge pull request #3 from brunops/tetris_gui

First version of Tetris GUI - EXTREMELY useful to find bugs