add level select state(currently empty but for one button), redirected from menu appropriatley.
Merge pull request #48 from garrettdalton/master

add level select state(currently empty but for one button), redirected f...
Merge pull request #49 from CothOmega/master

about us on index.html
incorporate fixed polar sprite
added multiple maps
Merge pull request #51 from georgexzeng/master

added multiple maps
add level select and main menu options to game over screen, slight gameplay tweaks
add music functionality, music playing in first lvl, prototype music mp3
Merge pull request #52 from garrettdalton/master

music, reviewed by Derek