Add ProcessID tracking to EnumeratedProcess object


ProcessID isn't currently being tracked, and while this hasn't been needed information before, it's something that will become much more useful in a future where this tool can run in the background (or be scheduled for periodic runs), and automatically flush the current workload of apps to RunOnce.
I believe that the best way for CacheMyWork to do this is to compare the current state of processes to the previously-gathered cache, and only add the new ones to the Registry. How can you know if an instance of IEXPLORE.EXE is new or old? Compare the PIDs.