Update CONTRIBUTING.rst

* Fixes minor  typos
installation: github repository url fix

* Fixes GitHub repository url used

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
Check VM kickstarter

* Adds bibsched to provisioning script.

* Removes bibsched from Procfile.
base: new BibTex formatter

* Replaces the old BibTex formatter.

Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>