Added python example for ReadDICOM.cxx

See merge request !308

this addresses #308

1. Modified the imports
2.Background to SlateGray
3.default size to default
4.modified the arg parse help

Adding the GradientBackground example

See merge request !307

Initial commit

See merge request !306

Utilities: Update OffScreenRendering for modern VTK versions

See merge request !305

`vtkImagingFactory` was removed in VTK version 6, but this example runs
just fine with any reference to that class removed.

1) Simplified the regular expressions
2) Comments in the examples are now handled correctly
3) C++ interface and implementation files are separately processed

Remove unneeded includes

See merge request !304