README: format the shields more consistently
installation instructions: fix two typos
restructure README.rst. fixes #314.

 - remove licensing from README
 - move contributors to their own file
 - remove manual installation instructions
 - add a contributing section
add hackday participants and Malte Swart to CONTRIBUTORS.rst
Merge pull request #343 from karyon/restructure_readme

Restructure readme, add hackday participants