Water level and bug fixes

1. The basic water level is designed

• There is a main island that "floats" in sky
• Main island has coins, health packs, and 3 types of enemies (sniper, platform enemy, and a laser enemy)
• Sniper enemy uses water guns
• TODO: Player should also use water guns, add more islands and use a boat to travel between islands?

2. Lots of bug fixes and tiny changes to sniper, main player, rifle, and platform spawner

• Rifle: removed white ball at the end, added logic to show water coming out of rifle
• Platform spawner: periodically checks if player near by (period is controllable unlike previously where it used to check every frame)
• Sniper: Blackboard and decision tree changes to improve logic when player is not visible, added null pointer checks for blackboard and player target access
• Main player: Changed the default pose of character