Assumptions:
1. User puts proper arguments for tranfficgen.py and collector.py

example:
    python tranfficgen.py "http://localhost:8080" 500 0.5
    python collector.py "http://localhost:8080" --interval 10
    python plot.py
    


resources:
1. Converting unix timestamp string to readable date:
    https://stackoverflow.com/questions/3682748/converting-unix-timestamp-string-to-readable-date

2. Enumerating a single line of a file.
    http://book.pythontips.com/en/latest/enumerate.html

3. pyplot tutorial
    https://matplotlib.org/users/pyplot_tutorial.html

4. Clearing the text file 
    https://stackoverflow.com/questions/2769061/how-to-erase-the-file-contents-of-text-file-in-python

5. check existence of file  
    https://stackoverflow.com/questions/82831/how-do-i-check-whether-a-file-exists-without-exceptions

6. how to give an interval between processes 
    https://www.pythoncentral.io/pythons-time-sleep-pause-wait-sleep-stop-your-code/

7. how to handle with urls
    https://docs.python.org/2/library/urllib2.html