Changes from old `defaultunits.lua` file (before rebase) to new `StructureUnit.lua` file:
Remove old quaternion import from `StructureUnit.lua` and `defaultunits.lua`
Use quotes instead of colons for import string
Use quat multiplication in structure rotation to fit terrain

They have some unexpected behavior not preserving roll/pitch

Fix checking unit being in the same army
Use PosXYZ to avoid table allocation
Fix being able to call `EntityCategoryContains(nil, unit)`
Move category check before distance calculation

saves 3 table calls

`Projectile.lua`'s `OnTrackTargetGround`

Use `dbg c` in console to see hitboxes then spawn vipers shooting at a target and make sure the lines end within the target hitbox.

This reverts commit b8e006b.

was non functioning mostly due to lazyimport addition and repr changes

Also updates the individual benchmark to simply require the benchmark file name and then run all the functions inside automatically

Upvalued engine function `VDist3` is usually the fastest

by adding Vector2 global

Make it return `angleX` aka roll on the +Z axis instead of the -Z axis
Also add comments explaining the negations of angles on the negative axes

It doesn't matter since it's a 2d rotation, but in case anyone is inspired by the function to use a quaternion for 3d rotation, the order should be correct.

Matches original manual quaternion multiplication's rotation order

use `SUB` instead of `UNM` and `ADD`

get/set metatable, rawget