Add Tests for easily testable components

[kkjamie]

TransformExtensions

• ForEach
• Reset
• SetPivot
• AddChildWithComponent
• AddResourceChild

TransformSnapshot

• ApplySnapshot

GameObjectExt

• AddChildWithComponent
• AddResourceChild

Collections

• ForEach
• ToArray

[kkjamie]

Started work on a few of these... dev_added_more_tests.

[kkjamie]

@HarryHodgson Can we reuse some of the tests for AddChildWithComponent and such from unity-hierarchy-behaviour