Mainly update glib annotations. Some Python 3 compatibility fixes.
Replace the 'allow_none' field on parameters with two separate fields:
'nullable' and 'optional'.
Many bug fixes.
Highlights from git shortlog:
Add GVolumeMonitor interfaces
Add --all option to g-ir-generate
Support glib-mkenums comment /*< flags >*/
Allow the use of the "Rename To" annotation for literal method renaming.
Add environment variable G_IREPOSITORY_VERBOSE
patch-ad removed as fixed in 82870258 (Bug 698438)
g-ir-scanner has a grown --xpath-assertions, --format and --inject options
Many bug fixes and translation updates.