GOP meta: policies 1-9 recorded

[Graham Percival]

I've added the "final" version of GOP-PROP 1-9 to the
Contributor's Guide:
http://lilypond.org/doc/v2.15/Documentation/contributor/policy-decisions-_0028finished_0029

Each proposal has the final proposal details, a few other sections
if I thought they were relevant, and a "discussions" section which
gives links to all the initial emails about each proposal.

Please take a look; I may have missed something.

Cheers,
- Graham