[FEATURE] Implements resampling from values on vertices to values on faces with the neighbor average method. (note that resampling method for datasets defined on faces, e.g., the value on vertices is calculated from value on faces was added in the previous QGIS release)
The default method is set to "none" for resampling from vertices to faces and to "neighbor average" for resampling from faces to vertices. Then the default rendering is now always smooth.
The mesh styling dialog now has new combo box for selection of resampling method for datesets defined on faces.
Also the analysis library has new class QgsMeshContours with export function for contour lines and contour polygons.
