avr: define ssize_t
Remove special case for atmega in kernel_types.h
board/arduino-due: removed newlines in periph_conf
Merge pull request #1990 from Kijewski/avr-ssize_t

avr: define ssize_t
Merge pull request #1991 from haukepetersen/fix_artuinodue_periphconf

board/arduino-due: removed newlines in periph_conf
Add UBJSON library