Reduces the visibility of all fields to private and create setters/getters
when necessary. Exceptions are fields with GuiSync as these need to be
public.
Reduces the visibility of internal methods to private/protected/default when possible.
Cells are only ever using precise for storing their items, thus there is
no need for a sorted collection with in general logarithmic time.
Storing them inside a HashMap for constant time is a way better solution.
Also adds an UnsortedItemList without fuzzy handling.
If anyone tries to use it, it will currently throw an
UnsupportedOperationException, Should the need arise guava Collections2
could provide a filter for it, but it is no alternative with heavy usage
of fuzzy access.
Also some code cleanup, reducing the visibility when not needed as
protected/default as well as removing actually unused methods.