Use Simpy 2. Create Packet and Source process classes.
Add Service class. Finish simulation code.
Finish Buffer_Queue. Add Ethernet simulation.
Comment Buffer_Queue.py. Add NodeCollections and setup methods for Nodes.
Backoff simulator finished.
Finish graphing code for part 1.
Add gitignore.
Modify gitignore.
Finish graphing code for both parts. Correct errors with function objects as parameters.