updated script methods, add script counts/errors

- added a test and report for scripts before they're actually applied
(resolves #100)
- appended a count of the currently filtered population when scripts are
applied
- updated all script functions to make any optional function args
non-optional, as it appears QJSEngine doesn't support them. also updated
information in the script dialog to reflect the function changes.
- removed obsolete role rating code
25.0 release, 40.10 layouts (win/linux)
Log to stderr on Linux systems.

This fixes #114 and removes the write to the current directory that
places files where users may not expect.

I assume that Linux users are familiar enough with the command line to
run a program and output errors to a file via 2>file or similar.