- Adds an abstract base class for profile generators,
QgsAbstractProfileGenerator. This is modeled off the approach
used by map layer renderers, where a QgsAbstractProfileGenerator
subclass object is created in the main thread and does all
required (hopefully inexpensive!) preparation steps necessary
to do on the main thread. Then a separate background thread can
later call the virtual generateProfile method, which does
the heavy lifting of calculating the associated profile. Later
the results of the profile generation can be retrieved back
on the main thread.
- Adds an interface "QgsAbstractProfileSource" for objects which
can create a profile generator given a QgsProfileRequest. Map layer
classes will implement this interface, but potentially 3rd party
(plugin based) objects can also implement the interface if they
also want to add custom results to the profile charts (e.g.
borehole trace lines).
