This is a step toward removing XML support from the v3 compute API.
First, we need to remove all of the tests that would fail once we start
ripping out the real code.
Part of blueprint remove-v3-xml-api
Change-Id: Ie2c280d5ea1e6b8756535deb05982a92561552db
Adds V3 API samples for cells and multinic extensions.
Bundling them together to save on review load
Partially implements blueprint v3-api-unittests
Partially implements blueprint v3-api-specification
Change-Id: I50840b3d900fbc8ff4f655e4188cc886d7065729
Russell Bryant