cleaned out optimization folder of the practice files.
began a program for Dijkstra, modified priority queue to store more info about each item.
Changed a variable name which could have caused confusion
commented instructions for Dijkstra code
graphnodes now store their index
Added relax function
priority queue now checks for duplicates.
added the moveInDirection method to move in one direction for a set number of ticks
Created method to convert list to an ArrayList.
Merge branch 'optimization' of https://github.com/santhnm2/CS196selfdrivingcars into optimization
Merge pull request #54 from santhnm2/car_logic

Cars now check road capacity when moving. Traffic light optimizations
added some comments, nodes now require road between them.
Merge pull request #57 from santhnm2/optimization

Optimization
Made some changes to the random map generation.
Merge branch 'master' of https://github.com/santhnm2/CS196selfdrivingcars
Small fix