* src/dense/ftdense.h: (FT26D6, FT20D12): New typedefs
* src/dense/ftdense.c: dense_render_line, dense_render_glyph now
use fixed-point numbers for calculation
Disabled SIMD for now
* src/dense/ftdense: Use SSE4.1 for final accumulation step
(FT_SSE4_1): Macro which checks if SSE4.1 is available
* src/dense/rules.mk: Enable linking for SSE4.1
Breakdown of what the files will contain
* src/dense/ftdenserend.c, src/dense/ftdenserend.h: The 'dense' renderer.
* src/dense/ftdense.c, src/dense/ftdense.h: The rasterizer for the
'dense' renderer.
* src/dense/ftdenseerrs.h: Common error defines.
* src/dense/dense.c: For building a single object of the entire module.