cmake fixes + added i2cslave

	modified:   CMakeLists.txt
	modified:   lib/default/Wire/utility/twi.c
	modified:   projects/CMakeLists.txt
	modified:   projects/blinky/blinky.cpp
	modified:   projects/combined/blinker.cpp
	modified:   projects/combined/combined.cpp
	modified:   projects/combined/test.h
	modified:   projects/generic.cmake
	new file:   projects/i2cslave/CMakeLists.txt
	new file:   projects/i2cslave/i2cslave.cpp