v1.19.0

MolSimToolkit v1.19.0

Diff since v1.18.1

• most_representative_structure now supports a selection string for the atoms keyword (https://m3g.github.io/MolSimToolkit.jl/dev/miscelaneous/#MolSimToolkit.most_representative_structure-Tuple{Simulation}).
• firstframe! and nextframe! were renamed to first_frame! and next_frame! for consistency. Legacy names were kept for compatibility and flagged to be removed in a 2.0 version.
• The get_frame function does not restart the simulation always, only if the required frame is before current frame. The function now returns the simulation positioned in the desired frame.