Move release notes and instructions to docs/

This follows the same format as Pootle.
Move API to the end of the documentation
Forgot this file
Try higher heading for the title
Add 1.9.0 and 1.8.1 release notes
Forgot to include 1.9.0
Nicer simple human release dates
Add section of GitHub hook, Bugzilla and commits

Commits formulated in the correct way allows comments to bugzilla bugs
and allows closing of bugs.

Fix bug 2895
Fix list
Reword bugzilla githb hook section

Turn it into a list for easier reading
Docs: Typo
Comment typos and whitespace
Enhancements for Langpack extension action

Add various things to make this script usable as a module for the
Langpack extension: mostly logging and exceptions
Documentation typos and clarification for name clashes