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
make: fix buildsizes* targets

also ignore BOARD_INSUFFICIENT_RAM boards
unify/make work BOARD filter
make: allow setting RIOT_VERSION externally

also make the RIOT_VERSION variable available in buildtest
native: reenable compilation on osx
Merge pull request #1475 from LudwigOrtmann/riot-version

make: allow setting RIOT_VERSION externally
make: make RIOT_VERSION fail-safe
make: add RIOTBASE to UNKNOWN RIOT_VERSION
Merge pull request #1476 from LudwigOrtmann/buildsizes

make: fix buildsizes* targets
Merge pull request #1499 from LudwigOrtmann/riot-version-fail

make: improve failing RIOT_VERSION
core:queue: remove ancient example
queue: remove inttypes clutter from core header
queue: remove unused generic functions

Closes #1153.
queue: add queue_t root type
avsextrem: use cc110x_ng as default transceiver driver