Started some overview documentation of the HaaS.

For a very generous definition of "started." The intent is for this to
become something a new developer can read to get up to speed quickly.
README: linked to overview.
More work on overview docs
Fancy ascii art diagram

Will write some prose to go with this soon.

Also hard-wrapped some of the text; this makes things easier in offline
text editors.
Fixed a typo.
Wrote about how the network is set up by the HaaS
Merge branch 'devel' into overview-docs
Issue#27: Add preliminary implementation for configuring active switch driver.
Add implementation for configuring switch driver.

This version now incorporates the changes suggested in the review comments
for the last commit: 797143e8efcc7edce0478f17879f8d494a177d0e.
Merge pull request #42 from CCI-MOC/configswitch

Issue#27: Add preliminary implementation for configuring active switch d...
Wrote a primer on vlans

This resolves issue #49.
Moved some floating tests into haas/_tests.

This is a convention we've been following on other branches.
Slight readability enhancement in the README.

The long url in the middle of the text made this a bit awkward to read
(and it didn't really fit within the line-length the document is
shooting for). The footnote style links are better for this.

I'm going to add some links to testing documentation, wanted to clean
this up first.
Wrote some documentation re: testing procedures.

This included adding a test-requirements.txt, to make the documentation
accurate. I also adjusted the pointers to documentation in README.md.
Wrote a bit about of managed vs. unmanaged switches.

Ritesh suggested that this would be useful.
Added some documentation about drivers.

Specificaly, the drivers package now has documentation about the standard
interface that a driver must implement. As noted, the error handling behavior
needs to be decided on and documented.
Reworded documentation to avoid implementation details.

The bit about no-ops isn't something the user should care about - the
functions just shouldn't be used at all.
Factored table names out into a single base class.

These can be autogenerated from the class name; there's no reason to have all of
that boilerplate.
haas.model: Added a comment about the meta attribute.

We want to make sure to remove this when the time comes.
Wrote an actual description for the README.