Improve and fix bugs i LocalFileSystem.
Extract LocalFileSystem::Share class as Protocol::Share class.
Reorder code in Protocol name space.
Make Protocol::Share constructor public.
Don't give access directly to shares map in LocalFileSystem.
Remove ExportShare and UnexportShare from Protocol name space.
Update Protocol test.
Update LocalFileSystemTest.
Update ErrorCodes in Protocol::DirectoryContentResponse and improve LocalFileSystem tests.