Added DAC driver files.
Code update: DAC basics (init & write)
Ajout i2c init, master transmit, master receive + samples
few updates in i2c driver
few tweaks into pji-test/main.c
few tweaks
works upon main.c
useless commit
added lm75b support
ajouts divers
Very improved version of driver. Added new return status, effective bytes count transmitted or received, comments harmonizations, documentation update, and (nearly) full I2C slave mode support.
Removed an old debug function now obsolete.
Little change on status 0x48's comment
Naming, storing rule, comments. Doxydoc is now live for I2C.
Finalized documentation.
Renamed dac test folder, updated sample test program.
Removed useless files
Merge remote-tracking branch 'bacara/driver/dac' into merge_bacara_drivers_dac

Conflicts:
	doc/Doxyfile
	rflpc17xx/rflpc17xx.h
	samples/adc-test/Makefile
	samples/dac-test/Makefile
	samples/dac-test/main.c
	samples/pji-test/Makefile
Fixes RFLPC_DIR path in dac sample
Changes indent to 4 spaces