Line of sight performance

[nstlaurent]

Checks per block instead of doing the segment split. I originally thought that per block checks would give incorrect results. Given the blockmap segment iterator runs from near to far blocks and it's only checking lines it works out correctly. This wouldn't work with hitscan traversal because it checks both lines and entities. You can hit a line in a closer block and hit an entity that is closer in a different block, so that was left alone.

Before:

Method	Mean	Error	StdDev
LineOfSight2D	162.2 ms	2.18 ms	2.04 ms

Method	Mean	Error	StdDev
LineOfSight3D	110.1 ms	2.03 ms	2.17 ms

After:

Method	Mean	Error	StdDev
LineOfSight2D	66.67 ms	0.381 ms	0.318 ms

Method	Mean	Error	StdDev
LineOfSight3D	42.92 ms	0.309 ms	0.274 ms

~60% faster with an ~85% improvement in the standard deviation, making this much more stable as well.