Issue #59: minor tweaks to documentation on philosophy and organization.

Ticket: https://github.com/backdrop/backdrop-issues/issues/59.

See code comments for some explanation.

One aim here is to de-emphasize voting. Yes, votes can be taken where needed, but in the normal course of things I expect project leads will give a lot of day to day direction without resorting to formal votes.

Other than that, a few minor spelling corrections and the like.