FabIO v0.5.0

The main new features are:

• All source files are now under MIT license (re-implement PCK/packbits
  in Cython)
• Context manager for fabio.open + automatic closing of files.
• Iterator over all frames in a file.
• Debian packaging for debian 7, 8 and 9.
• Use (patched-) ordered dictionaries for storing headers.
• Many clean up and bug-fixes
• New formats: mpa, jpeg and jpeg2000
• Provide "convert" and "viewer" scripts in the fabio-bin debian
  package.