Reimplemented TraitsInConstructOrder()
Added missing trait dependency
Moves a few start location/spawn traits to Mods.Common.
Adds Mods.Common usings where necessary.
Merge pull request #6894 from reaperrr/common06

Moved a few start location/spawn traits to Mods.Common
Merge pull request #6710 from huwpascoe/depends

Fixes #3160
Fixes #3568
Fixes #4894
Closes #6701