Initial commit for gyro sample

NOTE: This sample doesn't work with current firmware.  This commit just
      snapshots the initial version of the code before I clean it up.
      I will commit firmware changes and required changes to all of the
      other samples once I am done with this cleanup.
Cleanup gyro sample

This commit cleans up the gyro sample that I first added to the repo in
the previous commit.  This cleanup includes:
* Moving gyro calibration settings to ConfigFile.  Before the
  calibration values like temperature correction factors and scale were
  hardcoded in the program.  See adamgreen.config for an example of
  these new gryo calibration settings.
* Moved the correction of gyro readings (via calibration settings) from
  the main gyro.pde source file to HeadingSensor.pde.  This also meant
  modifying the HeadingSensor class to take the new gyro settings and
  even the older accelerometer and magnetometer calibration settings in
  a new HeadingSensorCalibration class.
* I removed some code from gyro.pde which I only had to aid in the
  determination of how to properly calibrate the gyro sensors.  I will
  move some of this code into a calibration specific application later.
* Upate the rotation quaternion in the serialEvent() method of the
  draw() method so that it can be run 100 times per second (sensor
  sample rate) instead of 60 times per second (frame rate).
* Removed the 'F' key feature which allowed switching between the use
  of filtered and unfiltered accelerometer and magnetometer readings.
Add gyro temperature output to firmware

I updated the firmware to return the gyro temperature reading over the
serial connection.  I updated the Processing samples to expect the 11
values that are now returned from the sensor firmware.