initial commit (schematics)

+ first version of README.md
+ first sketch of schematics

TODO on schematics:
+ power supply, charging and battery interfacing
further schematics development; layout started
further layout, got stuck somewhere...
board further
added ground planes
layout optimizations, tStop corrected
new layout
another layout try, looks much better now
layout improvements
corrected USB connector in layout+schematics
usb2seriel adapter for debugging and firmware uploading
usb2seriel