Add driver interfaces validation

This patch will expose a /nodes/<uuid>/validate subresource where users
could GET to trigger a validation on the 'core' and 'standardized'
interfaces for the driver the node loaded with. This will expose a way
to the ironic driver in nova to validate the driver interfaces of a node
before deploying it.

Change-Id: I1ca2b17c9752e7593214fe5b044595f6e63bed18
Fix auto-generated REST API formatting

Fix an issue we have with the formatting of our auto-generated
REST API documentation. Sphinxcontrib-pecanwsme does not like
single-line method doc strings.

This patch adds some description of the RESTful parameters.

For methods that take no parameters (eg, get_all) it simply
converts the doc strings to multi-line, even though this does not
adhere to PEP257. This is a work-around for a bug.
  https://github.com/dreamhost/sphinxcontrib-pecanwsme/issues/8

Change-Id: I0fde3314bf2d5c3e109ec85626d3e509ffd53c7c
Developer doc index page points to correct API docs

The index.html page of our developer web docs should now
reference the auto-generated API documentation, and we can
remove the out-of-date hand-written api-spec-v1.rst.
It served us well early on, but is impractical to keep up
to date with a fast-moving project.

Change-Id: Ie71f43ef363501d4c470485a011267755f41c5b3
Merge "Fix auto-generated REST API formatting"
Merge "Developer doc index page points to correct API docs"