drivers: Initial import of SPI low-level driver IF
drivers: fixes to the SPI low-level interface
driver: updated SPI driver interface
[SQUASH ME] added fixed speed values
[SQUASH ME] removed UNDEFINED from device list
[SQUASH ME] fixed signature of spi_transfer_reg()
[SQUASH ME] added begin_transaction, fixed doc
avsextrem: use cc110x_ng as default transceiver driver
tests: remove `test_` prefix

Closes #1485.
tests: fix APPLICATION name
Merge pull request #1503 from phiros/avsextrem_default_transceiver_cc110x_ng

avsextrem: use cc110x_ng as default transceiver driver
Merge pull request #1502 from Kijewski/issue-1485

tests: remove `test_` prefix
make: force traversal into PKG's, same as normal modules
cpu/board: added ADC driver for stm32f0discovery

- added ADC implementation for the stm32f0 cpu
- added ADC pin/device configuration for stm32f0discovery board
drivers/servo: fixed very stupid coding error
Merge pull request #1506 from haukepetersen/fix_driver_servo

drivers/servo: fixed very stupid coding error
cpu/board: added ADC driver for stm32f4discovery
lpc2387: change comment style for license checker
lpc2k: unify Paul Stoffregen license headers
Merge pull request #1314 from LudwigOrtmann/license_unification

License unification