Merge pull request #7 from lanhongjianlr/master

Bugs fixed in dynamic routing algorithm
Update constants.py
Update packets.py
Merge pull request #8 from lanhongjianlr/master

Bugs fixed in dynamic_routing_algorithm
Little Change
Delete something not needed
Tidy up TCPTahoe
Basic Vegas working now.
Fix Bugs:  Record flow rate and packet delay
FAST TCP Working now and revised graph output

Change graph output to be the average.
Buffer_occupancy is counted by number of packets now
Now windows size can be output correctly
Routing has some bugs. Commit for Lan to debug.
Merge pull request #4 from jvanbrug/master

add fast