make: refactor make system (parallelism, deduplication)

Almost everything was build sequentially in RIOT, because we employed
explicit for-loops to build directories (DIRS). This PR makes our make
system use normal dependencies to build directories.

All our compiling rules were duplicated, once for the application, once
for modules. This PR makes the application a normal module, removing
this duplication.
make: make DIRS usable for applications
make: create dependencies as side effect
make: use abspath for better error messages
Merge pull request #1326 from Kijewski/make-parallel-dirs

 make: refactor make system (parallelism, deduplication)
drivers: added set_absolute to timer interface
Merge pull request #1289 from haukepetersen/fix_drivers_periph_timer

drivers: added set_absolute to timer interface
More documentation
Actually call test_major_type_5_invalid
Merge remote-tracking branch 'upstream/master' into cbor