code cleanup

removed tftp library, digispark support, and driver
detection/installation support
added -D flag to the avrdude command
added registry key functions for windows

when on windows OS, the plugin uses the system's registry functions to
find the serial ports
Updated plugin version to 1.6 (multiple changes)

Added wjwwood's serial library for serial port communication. Changed
the way avrdude command is executed on Windows, so that a file
containing avrdude's output is generated.  Created function openPort and
exposed it to JavaScript, which allows implicitelly opening a port from
Javascript console. Added debugging function (enableDebug and
disableDebug) which are also exposed to Javascript.
Merge pull request #14 from codebendercc/updatedPlugin

Updated plugin