Updated README.md
Changed default port in arduino_params.yaml from /dev/ttyUSB0 to /dev/ttyACM0
Updated README file to include instructions on setting permissions on the serial port
Fixed extraneous backslash characters in README file
Added traceback call to arduino_driver.py to better diagnose serial port problems.
Added traceback call to arduino_driver.py to better diagnose serial port problems.
Added rosdep on python-serial to manifest.xml in ros_arduino_python package
Merge branch 'master' of https://github.com/hbrobotics/ros_arduino_bridge
Updated README to include dependency on python-serial
Updated README to remove the 'rosdep install' command as it is not working on some setups
Enhanced PID algorithm

Enhanced PID algorithm based on the series of blog posts at http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/
Specifically:
    1. Avoid derivative kickback - http://brettbeauregard.com/blog/2011/04/improving-the-beginner%E2%80%99s-pid-derivative-kick/
    2. Allow smooth on-the-fly tuning changes - http://brettbeauregard.com/blog/2011/04/improving-the-beginner%E2%80%99s-pid-tuning-changes/
    3. Reset windup mitigation - http://brettbeauregard.com/blog/2011/04/improving-the-beginner%E2%80%99s-pid-reset-windup/
    4. Bumpless initialization - http://brettbeauregard.com/blog/2011/04/improving-the-beginner%E2%80%99s-pid-initialization/
Bugfix: added resetPID() call in RESET_ENCODERS statement,
to ensure that PID gets reset when encoders get reset.
Bugfix - removed reset wind-up fix

Removed the reset windup prevention code, as the old code already
took care of that by only incrementing Ierror when output was not being clamped.
Fixed spelling typo in arduino_node.py
Deleted extraneous ROSArduinoBridge.cpp file
Merge pull request #6 from KristofRobot/enhancedPID

Enhanced PID algorithm
Removed unused self.shutdown variable in arduino_driver.py
merge