Release 3.8.4 (MC 1.7.4)

This is an important patch release:

• Now supports 1.7.4 and snapshots
• You can now create project from pack (use "My Projects" menu)
• Basic editing of models and shaders (14w06b)
• Remake of many dialogs (Unified GUI - colors, gaps etc, added headings...)
• Added GitHub bug reporting and improved crash log
• Fixed: "Save As" doesn't work - now works again, and better!
• Fixed: some crashes in image loader (now it uses "error" images instead of null)
• Fixed: external editors on Windows unable to save (unclosed resources in image loader)