Changed sprite. Doesn't open its mouth anymore when it jumps.
Implemented basic ai for waterballoon mob.
Ai pathfinds using player's coordinates picked up from Level.java
Implemented basic follow AI for waterballoon mob.
Also implemented sight range for waterballoon mob, where if the player
is far enough the mob will not follow.
**Still need to figure out a good method to implement wandering...**

Last cleaned some variables up in the abstract classes. Took redundant
variables out of MainBulletParticle and put them as protected in Entity
so all classes can just call from that.