HDXP: Running multiple threads in one step of a Visualization

[MikePlekan]

This idea is for having the hdxparallel engine run multiple threads before updating the screen again(aka. one step). This would bring the simulation of the parallelism closer to real parallelism.

Some tips/ideas for implementation:

• The scheduler mode functions(RR, RANDOM, SJF, LJF) are going to need to be updated to pick N amount of threads per call.
• The callEvent function will either need to run multiple threads or be called for each thread picked. I would recommend callEvent running multiple but I think either will work.