Added a functional Park Simulation

In this version of the park simulation:
 - Patrons enter the park at random times
 - Patrons first visit vendor 0
 - Patrons choose rides randomly, based on their popularity (with there being a 95% chance of not choosing the same ride twice)
 - Patrons take the correct amount of time to walk from one venue to another
 - Venues have a limited queue size, which patrons check before entering the ride
 - Venues serve a limited number of patrons per hour
 - Venues take the correct amount of time to serve a patron
 - The simulation runs for the correct time of 12 hours

The one major requirement that this simulation does not satisfy is that patrons do not yet leave the park.
I did a test run of 1000 patrons for 12 hours, and everything seemed to work OK then.
I also have not added requirement numbers in the code comments.
Merge pull request #2 from dbassett/patch-1

Added a functional Park Simulation