Merge commit 599964f into mbed-events/equeue

599964f Moved to tick + generation counter to mark in-flight events
02ce85d Restructured dispatch to calculate wait after dispatching callbacks
52e0aa2 Reorganized event back-references to be easier to read
be5ffc1 Fixed uncalled destructors in equeue_destroy
eb6eee1 Fixed small corner cases dispatch logic
43e609e Renamed equeue_sema_release -> equeue_sema_signal
e638d20 Added slotting for sibling events in queue
c4d4839 Moved to segmented dispatch
7937a76 Moved to constant-time event cancellation
f602cb5 Adopted size_t where applicable

Author: geky