First SIMD Implementation

[dangmoody]

Still not finished (and definitely still in preview), but definitely enough to bank into master for now.

SSE versions of all of the currently existing math library functions minus the following:

• Component-wise comparison of less/greater than and equal-to functions for register vectors/matrices.
• Matrix rotations.
• Angle between 2 vector registers.

There's also other changes in this PR too that's not related to SIMD, including:

• Doxygen docs are now generated as part of the generation, instead of a separate .bat file.
• Generation timer is now also supported on Mac OS/Linux.

The licenses of the code have also changed. Now the generator only is in GPL, whereas the generated code is now licensed under MIT.