Add lchan and timeslot FSM charts to illustrate planning of how osmo-bsc should
handle lchan assignment and release.
Modify assignment, handover, lchan-release charts according to the new plan.
Change-Id: I18d60de5ee932c962aad0a532965a55d570bb936
In doc/, add two message sequence charts with lots of implementation specifics,
to clarify the current code state. Mark various problems in red notes.
This chart and others should help to illustrate future code changes as I go
along refactoring handover, lchan allocation and adding inter-BSC handover.
Change-Id: I20999e938441d4fed2d37462b262b74a696f616d
Neels Hofmeyr