WIP convert blitting surfaces to RGB

Transparency may not work;
Health bar doesn't work
Improved background tinting
Implement blended blitting (#129)

Rename color_t fields to r, g, b
Adjust gas cloud tints
Implement HSV-based tinting
Update cbehave
Fix health bar blitting (#129)
Clarify license of HSV conversion code
Fix last row wall drawing (fixes #131)

Extend Y_TILES by 1; 3 buffer rows
are needed: 1 for rounding, 1 for walls,
and 1 more for odd resolutions
Fix brightness setting

Brightness applies to all pixels
Fix editor compile (#57)
Refactor blit clipping to graphics device

Add DrawPointMask
Lower automap overlay brightness
Refactor pixel/color conversion
Move blit functions to drawtools
Refactoring
Draw out of sight tiles as darkened (#72)
Display unvisited tiles as black (fixes #72)

Refactoring
Remove automap array
Add sight range (#72)

Sight range and fog are configurable
Fix automap exit drawing
Cleanup draw functions
Fix door drawing in fog (#72)

Plus some refactoring
Add blob shadow (fixes #16)
Fix crashes from out-of-bounds shadow drawing (#16)
Add reload bar (fixes #95)

Refactoring