Completely remove the old session save code that has been
superseded by the srzip output module. Also refactor a bit,
plug a number of leaks and tighten the error checking.
The confusingly named sr_log_logdomain_set() simply set a global
string prefixed to the log message by the default log callback.
This is pretty much useless, misleadingly named, and not used by
either sigrok-cli or PulseView.
This fixes a build problem due to the reduced include search paths
introduced by my recent changes. Also fix a couple of other
includes to use angle brackets.
Daniel Elstner
Soeren Apel
Martin Ling
Joel Holdsworth
Uwe Hermann