Collision System Micro-Benchmarks

[randomPoison]

We should have micro-benchmarks for each of the parts of the collision system in order to make it easier to do targeted performance improvements. The most important parts to test are:

• Collider tests (sphere-sphere, OBB-OBB, sphere-OBB).
• Grid lookup times (this looks like it might be one of the biggest bottlenecks, so having good numbers here would be helpful).
• Overhead on inserting collision data into the list of found collisions.
• Overhead on iterating between grid cells.
• Converting a world point to a grid cell.
• Calculating the bound volume from a collider (sphere and OBB).