Clean up non-spec output in flavor extensions
Clean up non-spec output in flavor extensions

Adds option to cache flavors in the request object like instances.
Modifies the flavorextradata extension to use the cache and optimizes
tests. Adds flavor_disabled extension to control the extra data and
includes tests. Fixes api samples to show the new extension.

Fixes bug 1043585

Change-Id: Ie89df24a2891e3869d3fb604e07c79e8c913f290

n0ano/ganttclient