refactoring: new method for persisting autoload cache
refactored: calling _persistAutoloadCache once at the end of _setPersistable method
refactoring: added new method _persistClassMethods
refactored: added new method for persisting included modules
refactored: new method for persisting singleton classes in _setPersistable. added newlines at the end of the files
Merge branch 'stefan/reautoloading-existing-modules-v2' of github.com:MagLev/maglev into stefan/reautoloading-existing-modules-v2