Packge migration some minor additions.
Passing error pointer along in a method, was NULL.
Some renaming of methods to get the message across.
Added some description for the collision of folder names.
Removed obsolete renameMap.
PackageMigrator tests refactored.
ProjectSettings and packagemigrator stateful per test.
Merge branch 'feature/#501_4_migration' of https://github.com/NickyWeber/SpriteBuilder into feature/#501_4_migration
PackageMigration two more tests added.