Added MP3 playing

- Note that this requires restructuring the build script.
Updated the build script for dependencies

- Made build script merge lib jars with the distribution jar.
- Added new instructions to README.md to account for the new build
system.
- Changed the distribution build target to the project's root directory
instead of the parent of the project's root directory.
- Added the distribution build target to .gitignore's entries.
Removed incompatible resources to fix #28

Credit for "310 - World Map (Loop)" and "295-B - Insidia (Battle Loop)"
goes to Aaron Krogh. Be sure to drop a link to him and his site on
https://soundcloud.com/aaron-anderson-11 before the game is released.