Batcher 0.3 Released

Redesigned user interface:

Replaced the folder chooser widget with a folder chooser button.
Procedures and constraints are now aligned vertically.
Adjusting settings for procedures and constraints now immediately updates the preview for improved feedback and interactivity.
Multiple edit dialogs (one for each procedure/constraint) can now be displayed simultaneously.
Edit dialogs for procedures and constraints are no longer separate windows and are hidden/shown simultaneously with the main dialog.
Completely reworked the custom procedure browser. You may now preview and tinker with a procedure/plug-in/script directly from the browser dialog before adding it to the list of procedures permanently.
In edit dialogs, replaced PDB parameter names with human-readable descriptions where available. The names are displayed as tooltips in case a user wants to track down issues with a procedure.
Moved detailed information about a procedure/constraint from a tooltip to a button showing a popup.
Given the changes above, adjusted dialog dimensions, positions of separators and spacing/margins/border width.

Bug fixes:

Added executable bit to the main batcher.py file. This could otherwise prevent the plug-in from being registered (i.e. from appearing in GIMP) on Unix-like platforms.
Fixed a crash for PDB procedures containing GIMP resources (brushes, palettes, gradients, patterns) as settings.
Prevented errors for PDB procedures with array arguments requiring a non-zero number of elements (e.g. pencil).
Fixed an issue where color parameters for some PDB procedures could not be adjusted.
Fixed redundant preview updates when the main, edit or procedure browser dialogs (re)gained focus.

Other changes:

Renamed the Export Layers Now menu entry to Export Layers (Quick) for hopefully greater clarity.