Add flexible versioning scheme

Add flexible versioning scheme

GLib introduced macros that allows defining the lower and upper bounds
of the API to be used by application code.

The lower bound allows to define the minimum version that will trigger
deprecation warnings; the upper bound defines the maximum version that
will trigger compiler warnings for unavailable symbols.

This scheme allows gradually porting application code to a new version
of the API, especially in case of resynchronization after multiple
development cycles.