Refactor simple_vlan unit test

The new switch driver 'test' records changes and lets you query them.  It also
provides a function 'reinitialize' that clears its state---make sure to call
this between each test.
Implement and test complex_vlan driver

Fix a bug in deployment tests along the way
Better document simple- and complex-vlan drivers
Merge pull request #379 from gsilvis/complex-vlan-driver-2

Implement complex_vlan driver