API layer documentation

* Discuss the WSGI layer of Neutron
* Describe the startup code that creates the WSGI application
* Briefly discuss the URL routing and resource creation

Change-Id: Id82a2a5679d7e29c0a19d1a20942a9249946b011
Remove individual cfg.CONF.resets from tests

oslo.config.CONF.reset is added to cleanup in BaseTestCase, so it does
not need to be done by individual test cases.

Change-Id: I5fced5c2d480e78e5bb7cc150f0b653313884456
Closes-Bug: #1291144
BigSwitch: Watchdog thread start after servers

Start the watchdog thread after the servers have
been initialized.

Closes-Bug: #1293799
Change-Id: Ic7ae1f55bd7faed6edde84d9d0b52fc8fe7a1fc1
Add session persistence support for NVP advanced LBaaS

Change-Id: I2042894755cdaf54b2bc39e58028746aa7c1e8ea
Closes-Bug: #1256243
Mock agent RPC for FWaaS tests to delete DB objs

This changes the firewall service unit tests to
mock the RPC calls from the firewall service to
the agent. This allows the tests to fake the
agent response RPC that removes the firewall
from the DB so the all of the other objects that
the firewall depends on can be deleted.

Closes-Bug: #1288441
Change-Id: I32462ab5557b9c52328bf6a23a12efc2d799644c
Ensure to count firewalls in target tenant

Previously admin tenant cannot create a firewall if other tenant
already created a firewall. We need to count firewalls only in
a target tenant.

Change-Id: I3e6d151d00d4a487bdd858e94929fab8960511a2
Closes-Bug: #1258438
Merge "Remove individual cfg.CONF.resets from tests"
Merge "Mock agent RPC for FWaaS tests to delete DB objs"
Merge "Ensure to count firewalls in target tenant"
Merge "BigSwitch: Watchdog thread start after servers"
Merge "Add session persistence support for NVP advanced LBaaS"
Merge "API layer documentation"