Memoized Value refactor proposal

Memoized Value refactor proposal

The Memoized value and file modification service architecture needs a rethink to simplify it. Below is the proposed interface for the new approach.

Overview:

• FileModificationRegistry will now control access to last modified information
• MemoizedValue doesn't change much at all
• The memoization logic will be removed from FileInfo. This class will be renamed to MemoizedFile, extend java.io.File and cache the reponses from the superclass by using MemoizedValue
• We will remove the need for FileModificationServices. This will be replaced by a single (optional) thread that will detect changes on disk and updateLastModified values in the FileModificationRegistry