framebuffer: fix alpha blending
cleanup
Some Makefile love
First video mixing working (hacky)
software/videomixer: framebuffer enable/disable
Merge pull request #1 from fallen/makefile-001

Some Makefile love
top: integrate ADC for pots
software/videomixer: connect crossfade and blackout pots
timer: atomic reads
Add GPIO buttons and LEDs
software/videomixer: better pot calibration
software/videomixer: support additive blending (enable with SW1, status on LED)
framebuffer: saturate instead of overflow
dvisampler: report the word error rate
software: add nofloat libbase for size-optimized binaries
Simplify system ID
Use migen.fhdl.std
Use new memory port API
dvisampler: increase frequency of reports to avoid missing WER values
bios/linker.ld: flash -> rom