Add model for networking journal entry
Implement journal-emptying function and server
Defer network operations

Now the API calls 'node_connect_network' and 'node_detach_network' simply make
a journal entry and return.  This breaks 'project_detach_node' and
'delete_network'---they gain an additional check.  Several tests now
explicitly perform the journal, to mimic the old non-deferred functionality.
Add another abstract model, AnonModel

This one has a 'id' (primary key), but not 'label' (user-visible name).
Improve docstrings for deferred network operations
Process networking actions in order
Merge pull request #296 from gsilvis/async

Async
Merge pull request #300 from gsilvis/cli-json

Refactor use of 'requests' into helper functions
Implement null auth backend

Authentication/authorization backends belong in haas/auth_mechanisms .  There
is CLI support, based on requestlib's pluggable authentication mechanism.
Add database-backed user/password authentication scheme

In this model, there are three kinds of groups of people that can be allowed
to perform an operation: anyone; anyone with access to the projecct, as well
as administrators; only administrators.  Right now, which operation has which
property is not tunable.

In implementing this, operations that anyone can perform have had their
'authorize' checks removed entirely.  This is not a very consistent way to do
this.  It also has the property that even unauthenticated users can perform
the action, which (depending on circumstances) may be desirable or not.

Also included is a script to create an initial admin user.
Clean up project/user check in db auth mechanism
Clean up import graph