[SQUASH ME] netapi: address @OlegHahm's comments + some formatting
[SQUASH ME] netapi: add demuxing context to reg command
[SQUASH ME] netapi: make current_thread registration inline
Merge branch 'netdev-proto' into basic_mac
sys: net: Initial import of a basic MAC protocol layer
unittests: provide unittests for basic_mac
[SQUASH ME] unittests: add missing semicolons on macro calls
[SQUASH ME] unittests: use global tests macros instead of random values
[SQUASH ME] basic_mac: Update doc to rename
[SQUASH ME] unittests,basic_mac: add proto to netdev_hlist_t struct
[SQUASH ME] basic_mac: adapt for registry context