Merge remote-tracking branch 'upstream/master' into fastrender
Raster drawing uses common get/setpixel methods

Instead of directly accessing the video array in each raster method, use
functions which can be changed once instead of changing each access.
Speed up + clean up rendering

Move OpenGL #ifdefs into their own function, leaving the SDL code much
tidier.
Apply logic to glow and blur rendering to avoid drawing unneeded pixels,
speeding both up by a good margin.
Parallelize render_gravlensing for a much-needed speed up on multi-core
computers.
Faster parts_avg, more efficient SPRK

The parts_avg function is relatively slow thanks to the use of the
floating point position.  The fast_parts_avg function uses integer
positions, making it faster.  Some elements have been changed to use the
new function.
The SPRK element was wasting time computing parts_avg when it didn't
need to.
Merge branch 'master' of https://github.com/FacialTurd/The-Powder-Toy into fastrender
Parallelize fire rendering

This is so unsafe.  Depending on how the parallel_for assigns indices,
addpixel can be called from two different threads in the same moment.
LoadWindowPosition has a better default position

LoadWindowPosition now positions the window on the nearest monitor if
the window is not inside a monitor.
Remove unused headers
Fix SPRK bug added with more efficient SPRK

Minor transmission issues.
Fix SPRK bugs introduced earlier

The fast_parts_avg method didn't exactly emulate the old behavior.
A minor SPRK bug affected some electronics.
Merge PowderToySDL
Cleaned up renderer, fixed stickman HP bug

A stickman with over 999 HP caused sprintf to overflow the 4 character
buffer.
Make rendering more like classic

Makes the rendering look more like the classic rendering.
Also draws auras after the other rendering so that it draws above
everything else.
I don't remember
aaa
Ok
Fixing things up