DOC: Improve Python package information.
DOC: Improve Python package information.

Improve Python package information:
- Make the reference in the long description match the package name and
  not the ITK project name.
- Use white spaces to avoid words in two consecutive lines being
  concatenated.
- Prefer ASCII double inverted commas.

Partially addresses:
https://github.com/InsightSoftwareConsortium/ITK/issues/326

InsightSoftwareConsortium/ITKTwoProjectionRegistration,InsightSoftwareConsortium/ITKTwoProjectionRegistration,InsightSoftwareConsortium/ITKTwoProjectionRegistration