simmer 3.2.1

New features:

• Add time-specific resource availability support (#21). Both resources' capacity and queue_size can change over time following a user-defined scheduling, which can be generated with the new function schedule.
• Advanced peek: inspect any number of future events in the event queue (8147820). For more details, see ?peek.

Minor changes and fixes:

• Fix steps grouping in plot_resource_usage (8da9b97).
• Fix incorrect trajectory behaviour when a rejection occurs inside a branch with merge=TRUE (#46).
• Fix a couple of segmentation faults in preemptive resources (f64f6b2).
• Improve verbose output (9013db0).
• New multiset-based event queue with unscheduling capabilities (a615fea and d6a9d67).
• A simulation may run forever (until the user interrupts it), that is, until=Inf is allowed now (f47baa9).
• New vignette on queueing systems.
• New vignette on Continuous-Time Markov Chains.
• Update and extend previous vignettes.