* Make box's mins and maxs static const.
* Use SSE to pack 4 indices into 1 128bit register, and shuffle to prevent duplication. Only 2 indices are used at the moment.
* Init vCamera once during call (MainViewOrigin() won't change during the execution of this function).
* Construct Vector3D for camera distance only once, using SIMD.
Obtain values of ConVar once a frame instead of checking within loop. There is no point changing the values while we are rendering. Thi sshould increase performance when drawing larger NavMeshes.
* Construct min/max for AI Script Network boxes using SIMD (significantly reduced instruction count!).
* Move NavMesh debug draw to dedicated class for future changes.
* Use SIMD to construct vertices into single XMM register.
* Use SIMD to construct origin and destination vectors from vertices.
* Deref 'navmesh_debug_camera_range' only once outside the render loop.
* Light code cleanup.
* Use SIMD to construct a Vector3D in a single instruction, instead of setting the vector fields individually.
* Store ConVar value as const bool outside loop.
* Slightly improved variable naming.
* Move AIN/NavMesh debug draw to ai_utility_shared.cpp.
* Use shift index + range for AIN debug draw.
* Added cvar for determining max distance between camera and tile (anything outside this range doesn't get draw).
Rare crash when the sqvm tries to look for an animation sequence on a missing prop_dynamic model (mdl/error.rmdl doesn't support animations), its purely to indicate there is a problem).
