Updater
-------
   - Remove dependency on zlib

User interface
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 - Make links clickable (about dialog)
 - Underline labels that have tooltips
 - Implant viewer
 - Fix caching to detect error documents
 - Create .bak files before cache files are overwritten
 - Reload skill in training after training finishes
 - Display skill queue / account information in GUI !!!
 - Tray icon when skill queue below some time (24h?) !!!

Skill Browser / Planner
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 - Add "Skill Group" column?
 - Priorities?
 - Move multiple skills at once!
 - Copy/Paste of skills between plans

 - Optional:
   - Subplan
   - Enabled skills through training
