Ciw

+ Ability to set seed. More docs. Fixes to tests.

+ Baulking implemented, and minor fixes to order of unblocking.

+ Priority classes implemented.

+ Python 3.4 and 3.5 compatible along with 2.7.
+ Data records now kept in list.

+ Ability to incorporate behaviour nodes.
+ Data records are now named tuples.

+ Re-factor inputs.
+ Simulation takes in a Network object.
+ Helper functions to import yml and dictionary to a Network object.
+ Simulation object takes optional arguments: deadlock_detector, exact, tracker.
+ simulate_until_max_time() takes argument max_simulation_time.