double unlock is same as locking :P

Fixes: reloadxml blocked

Because of uninstancied listener

- Solve deadlock:
  + associate all skinny_profile_find_session with the corresponding
    switch_core_session_rwunlock
  + lock the newly created session in skinny_create_ingoing_session
  + enhance rwlocks debugging
- Shared lines:
  + Inform shared lines on answering
  + Answering line has info after other shared lines

flush can be called several times

Merge made by -s ours

skypopen: better X11 interaction with a select on XEvents, no more setsockopt by default (tcp buffer size and TCP_NODELAY), setsockopt in config file