mods to clearinghouse.h and new messages

modified clearinghouse.h to change Motor so that is has two
constructors...one for motors with current sensing and another
constructor for motors without.  I need to test the reverse()
funtion in Motor
	new file:   messages/control_effort.h
	new file:   messages/pitch.h
	new file:   messages/plant_status.h
	new file:   messages/state_vec.h
added Position::position and used it in Motor
modified Motor.drive()

  - overloaded .drive to take a Direction::dir and pwm input
    directly without having to formulate a motorstate struct
Significant changes

  - Added a new gw::vector<class T> type that represents the
    mathematical notion of a 1 x 3 vector for holding sensor data
    from the gyro and accel.
  - Added basic vector math functions in the gw namespace to handle
    work on vectors (dot, scalar multiplication, cross, add, and
    normalize).
  - gw::vector and some of the vector math functions are a port from
    the Pololu libraries for the L3G gyro and LSM303 accelerometer.
added Pololu license to clearinghouse.h
Several small changes

  - Added the typedef for Time to clearinghouse.h
  - Updated bare_minimum sketch to include a few other libraries
    that would be uncommented
  - Updated the pitch and plant_status messages to use Time and
    changed theta in pitch to a float.
Significant changes

  - Added the 'blocks/' folder to hold gw components.  I've
    moved some of Mary Lou's blocks into this folder and this
    weekend I really need to clean up Alfreds blocks.  I want a
    cleaner library for the overall Arduino environment and this
    is a key to getting that.
initial state observer functioning
added deadband solver and updated gw_bare_min template
Deadband solver working as desired
working on deadband...not functional yet
deadband ready for testing
deadband compensation added to the gw::Motor

  - new private function deadband_compensate() takes the
    raw pwm signal and compensates for deadband in the motor.
  - set_deadband(int forward, int reverse) allows gw::Motor
    users to set deadband in the range [0, 255] and [-255,0]
    respectively for each motor direction.
  - use a script similar to the example in Glow_worm/examples
    called deadband_solver.ino to find the deadband for each
    motor once it is mounted in the robot.
brought quadrature.h into the gw/blocks folder