Historically the configuration used to be stored in layer's custom properties, but that does not scale
beyond simple rendering and so rule-based labeling introduced storage of configuration natively in XML elements.
That left us with two different ways of reading/writing labeling configurations. This work makes all configuration
to use native XML elements.
To keep compatibility of 2.x projects, reading of configuration from custom properties is preserved.
This commit also adds Python APIs for direct manipulation of labeling configuration through vector layer's
setLabeling() and labeling() calls.
QString methods
Using single quotes is a significant performance boost. Rough
benchmarks indicate the QString single quote methods take
about 15% of the time the double quote variants take.
Rationale:
- there was a lot of large objects passed by value, so potentially
there's a speed bump from this
- even for implicitly shared classes like QString/QList there's still
a (small) cost for copying the objects when there's no reason to
- it's the right thing to do!
* defer initialization of map settings until after QgsApplication is initialized
* disable local server test
* set ogr encoding in qgsserver testproject.qgs
