Added missing battle screen effects for target unit and second attack unit. Refactored weapon-based screen effects for battle animation sequence.
Applied dynamic animation sheet repositioning, resizing, and re-offsetting to mage_battleanim.js.
Fixed bug where enemy attacks triggering screen effects would not get flipped (screen effects from enemy attacks now flip to target appropriate target).
Added alpha opacity to screen effects in battle animation sequence. Fixed bug with incorrect reference to unit gaining experience.