Improvements in opening flowcharts

• Removed directories and files not ending in ".flow" from the list of flowcharts that can be opened.
• When getting a flowchart from a previous job, the list of jobs is reversed so the most recent is at the top.
• Enhanced the handling of parameters to support e.g. lists of values with the normal units attached. Used in e.g. thermochemistry to allow lists of temperatures and pressures with associated units.