simmer 4.1.0

New features:

• New getter get_selected() retrieves names of selected resources via the select() activity (#172 addressing #171).
• Source and resource getters have been vectorised to retrieve parameters from multiple entities (as part of #172).
• Simplify C++ Simulator interface for adding processes and resources (#162). The responsibility of building the objects has been moved to the caller.
• New add_global() method to attach global attributes to a simulation environment (#174 addressing #158).

Minor changes and fixes:

• Remove 3.8.0 and 4.0.1 deprecations (#170 addressing #165).
• Fix get_global() to work outside trajectories (#170 addressing #165).
• Fix rollback() with an infinite amount (#173).
• Fix and improve schedules and managers (as part of #174).
• Fix reset() to avoid overwriting the simulation environment (#175).