Forgot keywords.txt

• Added MAX_SPEED to keywords

Minor Adjustments

• Switch factor is user adjustable
• setBackLED does not break odometry any more
• Other minor adjustments

Cleaning, removed compatibility issues with Arduino 1.6.13 and 1.8

• Removed compatibility issues with Arduino 1.6.13 and 1.8
• Cleaned code and comments

Bug fix

Fixed: Correct version number in library.properties

Installation improvements

• Added hardware description files for ASURO board
• Removed broken support for ATmega168
• Instructions to install in user directory on Windows
• Tested with Arduino v1.6.12 on Mac and Windows

Documentation update

Some meta data and documentation was updated.