Fluid simulation upgrades

[turanszkij]

• Remove hard coded bounds
• Allow user to set up simple bounds or collision shapes
• Fluid rendering: maybe voxel based?

[turanszkij]

• Improve performance by implementing binned hash table instead of sorted hash table. [Done in: https://github.com/turanszkij/WickedEngine/commit/1ae278dc9b3b4f19da0a416094ce257d972f0791 ]

[turanszkij]

Hard coded bounds removed, now it supports custom colliders: https://github.com/turanszkij/WickedEngine/commit/8aad16113dade97a52ebc50abf1330db3eb1531e