Implement unreachable() for MSVC
Implement unreachable() for MSVC

That requires also defining likely() and unlikely().

Signed-off-by: Thiago Macieira <0ed1648d92ca0373297a182b1dba1b974ad10d88@intel.com>

thiagomacieira/tinycbor,thiagomacieira/tinycbor,intel/tinycbor,thiagomacieira/tinycbor,01org/tinycbor,intel/tinycbor,thiagomacieira/tinycbor,01org/tinycbor,intel/tinycbor,intel/tinycbor,01org/tinycbor