Make skipping first 4 bytes optional

This allows the parser to handle things that don't start with
length/tag.
Add pry to testing bundle group
Remove unused variable in NavStreamer.
Add AT*CTRL command to AtCommander

Also improved the specs so they are more readable and modular.
Add alias reset_watchdog for backward compatibility

I want the AT Commander methods to more closely reflect the low level
commands going to the drone.
Add ack_control_mode command to the commander.
Remove Gemfile.lock from git

Unlike applications, in libraries the Gemfile.lock file should not be
checked into source control. To do so would tend to force all users of
the library to use the locked versions of the dependent libraries.
Ignore Gemfile.lock
Add ack_control_mode command to NavMonitor

This was done to see if it improves the nav data stream. We still
reached a point where the nav data had stopped, so I don't think we
are there yet.  Perhaps we need better logging capability to monitor
program state along with the nav data.
Artoo compatibility: Allow UdpSender to get explicit socket.

Passing in a socket option to UdpSender allows the socket to be
created externally and passed into the sender. This is for Artoo
compatibility.
Artoo compatibility: Allow drone.start to disable NavMonitor

Artoo does not use the NavMonitor, preferring to handle the navdata
itself. By calling drone.start(false), a Null monitor is used.
Move option nav logic to initialize

Because programs will attempt to register callbacks before the drone
is started, deciding on whether the NavMonitor is enabled or not in
the start method is too late.
Bump to version 0.3.0

Ready for Cincy NodeCopter event, Sep 7, 2013.
Missed these two files.
Add tracker example program.
Ignore the examples/x directory
Add code coverage.
Fix spec description typos
Update the class diagram.
Improve coverage for Drone