Added Infantry units

Also, changed hoplite to match infantry, changed the collision detector
to account for attack range, and made some changes to rts.js (see
comments in file for details)
Tank js file ver1.0
Very basic skeleton of building class started.
add building function
started villager
Continued working on villager

merged in the building method and implemented weak attacking
Merge remote-tracking branch 'origin/factioning' into buildings
Merge remote-tracking branch 'origin/factioning' into Units

Conflicts:
	rts/src/rts.js
	rts/src/units/hoplite.js
Updated inheritance
Merge branch 'Units' of https://github.com/Jbtyson/cis580-rts into Units
Updated villager inheritance
Added getAttackRange to mousebox
Merge remote-tracking branch 'origin/start_end' into Units
Merge remote-tracking branch 'origin/start_end' into buildings
Re-enable start screen
Added playlist, soundtrack resource manager
Fixed looping once reach end of playlist
Add scrolling credits screen
Sound to start_end
Added soundtrack to credits