fix ordering in session construction so that new sessions and existing ones both work
allow waf to handle inconsistent case where cwiid.h is present but not the pkg-config file
fix language issue
commit some logic problems with the EngineDialog when change the driver/device name combos
fix missing initialization of two Session members, which fixes a crash during quit-without-finished-session
update buffer size duration (msecs) while displaying saved audio/MIDI setup state
more session construction order changes, and removal of n_physical_{inputs,outputs} members which were (a) not initialized early enough (b) not used anywhere except monitor bus connection.

Things almost make sense now.
various bits of polish for the latency tab of audio/midi setup dialog
end latency detection if AMS window closed while running detection (plus some non-functioning changes to try to get spinbutton text entry to work
a few DEBUG_TRACE improvements
check for an existing PublicEditor instance AFTER attempting to handle a key press in a window that has called relay_key_press(), so that normal key handling works there (e.g. audio/MIDI setup)
minor fixups for audio/MIDI setup spin buttons (now editable, as they should be)
Merge branch 'master' into cairocanvas