Py3k

This release brings support for Python 2 and Python 3 from the same source,
without any translation. Thanks to @pya and @woodscn for getting things started.

Pulls

• Automate spell check (#657)
• Fix gmsh on windows (#648)
• Fix sphinx documentation (#647)
• Migrate to Py3k (#645)
• gmshMesh.py compatibility with Gmsh > 3.0.6 (#644)
  Thanks to @xfong.

Fixes

• #655: When Python 2 and 3 are installed, Mayavi wont work.
  Thanks to @Hendrik410.
• #646: Deprecate develop branch
• #643: Automate release process
• #601: contents.rst and manual.rst are a recursive mess
• #597: Use GitHub link for the compressed archive in documentation
• #557: faceGradAverage is stupid
• #552: documentation integration
• #458: Documentation wrong for precedence of Lx and dx for
  NonUniformGrids
• #457: Special methods are not included in Sphinx documentation
• #432: Python 3 issues
• #340: Don't upload packages to PyPi, just add the master url