Removing excess players/enemies/animations

The reason behind this pull request is to try to have our enemies/players/animations reflect what they once were during our presentation at ACM's student/faculty Mixer. It seems that after adding in all the extra players, enemies and animations, the following problems came up:

* Directories became cluttered. While this is not a problem, we should focus on finishing the game with a small amount of working, stable units, and then finally extend our character base.
* Bugs came up, which were hard to track down due to all the changes. 

This pull request has the following changes:

* Moved all extra players into `extra_players` folder.
* Moved all extra enemies into `extra_enemies` folder.
* Moved all extra animations into `extra_animations` folder. 
* Removed all `requirements` from `main.js` and `enemy_spawner.js`.

I have also fixed up any discrepancies between animations, and fixed up a few here and there. In order to run this, you'll need the media files `media_2014-07-10_18_06.zip` located on Bitbucket. 

Things are much simpler now, the only entities that remain now are:

* Assassin (Hero player)
* Sage/Enemy Sage
* Wyvern Lord 
* King
* Dracozombie