progress on experience system
Merge remote-tracking branch 'upstream/master'
Merge pull request #41 from mk200789/master

modified experience system
Fixed minor bug with floating point experience gained. Minor code cleanup.
Rewrote battle animation sequence from scratch. Battle animation sequence now registers normal, critical, and magical attacks on a per-unit basis (provided unit has appropriate animations, stats, and weapon). Merged new experience system to new battle animation sequence. Improved new experience system and enemy item drop system to accommodate for all possible attacker/defender scenarios.

** Existing bugs from old battle animation sequence still persists. **
Fixed bug with battle animation sequence where health clamps references incorrect unit.
Fixed major bug when enemy initiates attack and enemy is defeated via a counterattack, the game would do weird stuff (ranging from game freeze to stacking battle animations).
Applied modified critical attack frames to hero_battleanim.js. Cleaned up hero_battleanim.js.
Modified checks for spell screen effects to be based on weapon (tomes) instead of affinity. Minor code cleanup.