some little things

Changes

• materials are now unlit to improve performance and visual clarity
• texture loading is now optional when loading meshes in case memory runs out (i need to multithread/implement an asset server for this anyway)
• duplication works much more smoothly
• missing shortcuts added back in
• render distance setting removed
• post save script actually works now
• improve texture finding to ignore normal maps and some default engine textures (might take longer tho :/)
• update repak version

Full Changelog: 0.13.0-alpha...0.13.1-alpha