class pPCA and rearrangements in RvtkStatismo

I got rid of the ugly bastard class pPCAconstr! Now there is only one shape model class that can be restricted by defining existing/missing coordinates and a given specific shape (function ComputeConstrainedModel() (I have not yet looked at the statismo methods to restrict a model, though).

Header files

Header files now reside in inst/include, thus future packages may use the already implemented routines (e.g. conversion between statismo and pPCA) by adding

• LinkingTo: RvtkStatismo in the package’s DESCRIPTION file
• adding RvtkStatismo to Import section in DESCRIPTION
• adding importFrom RvtkStatismo statismoBuildModel (or any function from RvtkStatismo) to trigger loading RvtkStatismo’s dynlib.

File layout

I made the file naming in the R folder more comprehensive and split a couple of very long files.

Misc

I added a converter between vtkPolyData and vtkUnstructuredGrid (courtesy of VTK examples in their Wiki), that might prove usefull when implementing more representers in the future.