Allow selecting returned JSON object attributes.

This makes working with the API easier by letting you return just the
attributes that you care about.
Make IP address allocation avoid deadlocks harder.

Make sure we get an exclusive lock on the network_allocations table
before actually trying to allocate an IP, and retry any failed
transactions that happen due to deadlocks.  This will keep the system
from trying to hand out the same IP in different transactions that
happen to be running in parallel.
Change the default logging level in production to info.

Debug was way too verbose.
Improve logging of fatal errors.

We were not throwing the complete exception message and backtrace into
the log.
Make docker-admin smarter about mounting things in /opt/opencrowbar.

This should help Derek out a little bit.
Allow the framework to mount other rails engines.

When the Crowbar web framework comes back up, do everything needed to
load all the additional gems, mount the engines, and load the additional
database seeds to finish the imports of any additional barclamps.
Fix barclamps_controller index action.

We don't expect to get an ID parameter, stop trying to load a single
barclamp when we want to return a list of all of them.
Remove version checking for the API in the barclamp controller.

The routes take care of all of that for us.
Get rid of application_controller methods we no longer use.
Make sure that we set v6prefix default value properly.

For new networks, we want to default to using an auto-generated IPv6
prefix if nothing else was passed.
Merge pull request #61 from VictorLowther/post-rails4-usability-tweaks-and-fixups

+2 Post rails4 usability tweaks and fixups