Add sd-reader code/lib (http://www.roland-riegel.de/sd-reader/)
Add #defines to uart.c for m32u4.
SD changes for m32u4.
Works now with my card (m328p).
Test raw SD read. Works (slow; w/enc 27kB/s, wo/enc 60kB/s).
SD code works on xmega (read 150kB/s).
Code cleanup (serial helpers).
Code cleanup.
Butcher (block r/w only) and move sd_raw code. Fix 512.
Merge branch 'sd' of github.com:flabbergast/enstix into sd
Fix LEDs for avrstick.
Update README with microSD stuff.