updated Makefile to generate .def files, removed .sln file
improved .def file generation, moved externally visible constants to .inc files
implemented loader menu user interface
implemented serial receive and transmit
loader input loop: now polls both serial interface and keyboard
loader now accepts data
bin2ram.py now supports the loader program
bin2ram: close file to flush all data before printing "Done."
loader now has a working progress bar, added math.asm for division
loader shows remaining byte count; fixed progress bar
added menu item; minor color changes; reordered code in Makefile
made SPI driver independent from video, added files for sdhc support
minor formatting improvements, added Z80 identifier to asm sources
Merge remote-tracking branch 'origin/master' into filesys

avoid conflicts due to code reformatting in master
rewrote SPI to use interrupts, implemented SDHC card detection and idle command
sdhc init and block read
fixed some errors
updated python scripts to always use python2
Merge branch 'master' into filesys

this branch needs the fixed tool scripts
fixed SDHC initialization, block read seems to work now