Add hasDefaultValues method to QgsDataDefined, add some tests
* fix cppcheck warnings
* some sip updates
* [API] fix spelling QgsMultiRenderChecker::drawBackround
* [API] fix spelling QgsSymbolLayerV2Utils::drawStippledBackround
* [API] fix spelling QgsMapSettings::layerTransfrom
Sort members in api docs
[FEATURE] Live heatmap renderer