Cool new manifest features: private projects, annotations, and overrides, oh my!

Change-Id: Ife651e0f004763527fd1334eba10cd43d20b5035
Reviewed-on: http://review.couchbase.org/42201
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>