PyCorrFit 0.8.8

• Improved support for "ALV-7004" files.
• If you install the GUI with pip, you now need to include
  the GUI requirement: pip install pycorrfit[GUI].
  The GUI depends on matplotlib and wxPython which is not
  required for scripting with the pycorrfit module.
• Bugfix: missing version string on SuSe linux (#101)
• Under the hood:
  • Python entry point script replaces "bin/" script
  • Windows build system hosted by appveyor.com
  • MacOS X build system hosted by travis-ci.org
  • New builds use wxPython3 (#85)
  • Unicode support without reload(sys)
  • Error messages are more verbose