Bumping to Houdini Version: 13.0.513
Houdini Engine Version: 1.8 (API: 14)
Start removing elements from the end of the array attribute

The index now refers to a valid element.
Reuse existing OutputGeometryPart when number of parts change

OutputGeometry now stores an array of OutputGeometryPart pointers
instead.
Rename methods and variables in OutputGeometryPart
Move the code for accessing MDataHandle inside the compute method for each geometry type
Clear out the mesh if the part doesn't output a mesh

Since Maya's mesh node doesn't handle empty mesh properly, the mesh will
still be visible until a sync happens, where the mesh node itself is
removed.
Refactor the code for clearing out curves