- fixed missing getShapeFunction/getGradShapeFunction + return all sf
  at once so we can implement MElement in term of these consistently
  (w or w/o FunctionSpace)

- can now merge multiple meshes and remove duplicate mesh vertices
  (useful e.g. when merging several STLs)

- added easy interface to create model-based postpro datasets on the
  fly + use this for mesh quality stats

add string.h needed for strdup and strcmp with some gcc version

geom entities

* no lc at points == MAX_LC (-> lc/10 like for STEP & co)
* don't specify a char length at points by default when creating a geo with the GUI