adding code to do NAT type detection.
update python code, move hardcoded ip and port to config'
update code, adding comment, remove unnessary stuff.
update version of uproxy-lib
remove unnecessary code in server, adjust time on client to make it more reliable.
do multiple udp send to deal with udp packet loss.
remove freedom module dependency, as we have it through uproxy-lib. update server code as suggested in comment."
remove unused entries in config file
add comment to server code about deployment. other nits to address comments in review.
remove unused uecho.py, rename server directory to be python-src to make more sense
add readme file to explain the usage of 4 files.
rename files to make more sense
Merge pull request #9 from uProxy/shanjian-update

adding code to do NAT type detection, plus other changes, see comment below.