Created README

Added a little bit of info about RPL.
Add support to motelist for shimmer devices

Check for the FTDI FT2232 chip on the Shimmer docks and Span, as well as the FTDI FT232 on other devices
Merge pull request #183 from lab11/rpl-no-warning

Removed Compiler Warnings from RPL Stack
Merge pull request #193 from mikehealy/motelist

Add support to motelist for shimmer devices
Merge branch 'master' of github.com:tinyos/tinyos-main