Spec preferences unweirdification

Summary

The goal is to group and sort the Inkscape Preferences dialog's pages. Lots of new things have been added revision after revision, and it's really crowded now...

Release Note

Changes planned to be merged in 0.49.

Groups

Pages could be grouped as follow:

Tools

(Same group as in 0.48, but reordered so that it reflects the way the tools are actually sorted in the UI).

Interface

• Windows
• Grids

Behavior

• Selecting
• Transforms
• Scrolling
• Snapping
• Steps
• Clones
• Clip paths and masks

Input-output

(previously Import/Export)

• Input devices (previously Mouse)
• SVG output
• Color management
• Autosave
• Openclipart

Not grouped

• System
• Bitmaps
• Rendering
• Spell check

Options

• "Simplification threshold" from Misc to Behavior (parent page)
• "Show filter primitives infobox" from Rendering to Interface (parent page) [but do we really need it?]
• "Prevent sharing of gradients" from Misc to Tools>Gradients
• "Use current directory for Save As..." from Save to Input-output (parent page)
• "Add label comments to printing output" from Misc to Input-output (parent page)
• "Latency skew", "Pre-render named icons" and "System info" (refactored) from Misc to System
• "Default export resolution" from Import/Export to Bitmap
• All autosave options to Input-output>Autosave

Further possible improvements

• Add default path for Save and Save As in Input-Output (parent page)
• Move the toolbars related options from Interface to Interface>Toolbars