- fixes for handling Polygon25D
- add QgsAbstractGeometryV2::convertTo( QgsWKBTypes::Type type ) for
easy conversion between geometry types
- fix crash when calculating perimeter with no exterior ring
- ensure that added rings respect dimensionality of polygon (avoids
issues such as polygons with z having a ring without z, or a
Polygon25D with LineStringZ rings)
- if a curved ring is added to a polygon then a segmentized version
of the ring is used (can't have a Polygon with a CircularString
ring)
- when calling setInteriorRings, make sure empty rings are skipped
and that all rings are converted to correct type for polygon
- don't crash when requesting or removing interior ring with
index < 0
- prevent creation of a QgsPointV2 with a non-point WKB type
- fix bounding box was not invalidated for some modification routines
- if WKT type is PointZ/M/ZM and not enough coordinates specified,
initialise extra coordinates to 0
