Deprecate wait() in favour of acquire(), try_acquire(),
try_acquire_for() and try_acquire_until().
Brings Semaphore more into line with CMSIS-RTOS 2 (which uses "acquire"),
itself (as it has "release"), and other classes having "try", "try for"
and "try until".
Also steps away from vague "wait" term - the primary operation here is
to acquire the semaphore, and this will of course sleep.
Make Nanostack an OnboardNetworkInterface, implementing
add_ethernet_interface so it can use EMAC drivers.
Can now be used via EthernetInterface, and be the system's default
network stack.
Legacy support for NanostackEthernetInterface retained. Some
restructuring of mesh interface code to fit into the
OnboardNetworkStack:::Interface system.