Increase Readability of Available Presets

[simon04]

As the number of external presets increases, the preference dialog "Available presets" gets more and more unreadable.

Here are some ideas to improve on that:

• Sort the presets by name
• Get rid of presets, tags, … in the preset description
• Prefix by country code, e.g., "[AT] plan.at source"
• Rearrange the three parts "Available presets", "Active presets" and "Icon paths": position them on top of each other to increase the width of the former two
• Display "Available presets" in a table
• List some defined presets for each "Available presets"
• … [further ideas are welcome]