DOC: rewrite and improve the 'contributing' tutorial; a Git 'mini HOWTO'
DOC: minor formatting tweaks to Benny's "contributing" page
DOC: slightly shorten and re-structure the "Contributing" tutorial

- prefer lower headline levels, more structuring
- turn some headlines into bullet lists
- cross-link to the "Building Lumiera" tutorial
DOC: complete the "Contributing" tutorial with some proposed tasks to work on
Debian/Repo: reorganise the Git repository URLs

all debian package repositories are now located below
git://lumiera.org/debian/...
DOC: update and polish the building tutorial
DOC: some further round-up and polishsing
release prep: remove defunct autotools buildsystem
release prep: clean-up obsolete information
release prep: bump version number

...this will be the second preview release
Lumiera is still in pre-alpha stage, and thus there
are no proper releases, just preview snapshots
from time to time.

But we're providing Debian packages allready
Pre-release 0.pre.02

This is a development snaphot pre release of Lumiera.
Update README, AUTHORS, LICENSE and similar release docs.