handle part files correctly
first check if a extension exists before comparing it
check shares for the real file and not for the .part file
fix part file handling and real size calculation, this should also solve #4581

Conflicts:
	apps/files_encryption/lib/stream.php
if the files doesn't exist yet we start with the parent to search for shares
coding style fixes
remove error logs
remove some error_logs
remove some more debug output