native: add and use callback type
Merge pull request #1898 from LudwigOrtmann/native_callback_t

native: add and use callback type
drivers/mq3: added driver for alcohol sensor
tests: added test for MQ-3 alcohol sensor driver
board/stm32f4discovery: added ADC feature
Merge pull request #1703 from haukepetersen/add_driver_mq3

drivers/mq3: added driver for MQ-3 alcohol sensor
Enable SPI for udoo boards
Merge pull request #1897 from PeterKietzmann/add_udoo_spi

boards/udoo: added peripheral SPI definitions
drivers/at86rf231: refactoring of the at86rf231 radio driver

* deploy extended operation mode
* cleanup
* implement netdev 802154.h interface
drivers/at86rf231: suppress cppcheck warnings in 802154.h

Suppress cppcheck warnings of class unusedStructMember because
this interface is not used yet. Remove these comments once it
is used.
SQUASHME: addressing comments
SQUASHME: addring other comments