Fix for Mac OS X tab widget icons

Suppresses the icons used on the tab widget in the Configuration dialog
on Mac OS X. On that platform, icons do not render properly when the tab
is active, leaving a large gap.
Prevent accidental processing of bare filenames

When using the mass generation mode with bare filenames, these were
consumable again through the router. This fixes that possibility by
introducing a new regex and strip against strings that are obviously
generated by the add-on.
Only display scary bare filename warning if needed

Changes this label to be toggled on or off depending on the current
state of the user's behavior and handling options.