Use remove_if to clean up junk point_seg
Remove assembler-only variables
Use color_t for color values
Change gr_fade_table to array<array<>>
Remove unused find_hitpoint_uv l parameter
Pack render side edges
Optimize out unused g3_set_special_render arguments
Fix !OGL build in gr_internal_color_string
Inline fixdivquadlong
Pass quadint to quad_sqrt
Fix array underrun in redraw_messagestream
Make alloc_vert/free_vert static
Throw on invalid homing_flag
Use array<> for Segment_points
Use array<> for Players
Fix D1 homing weapon regression

01f1553 intended to make D1 not treat proximity mines as chaff.
Instead, it removed the test for whether the object was an acceptable
type.  As a result, all homing weapons lock onto the nearest
non-excluded object of any type, which is the homing weapon itself.  It
then flies in a straight line trying to catch itself.