Changes:
 - List now only updates 2 times when doing for instance a lock of a file. Once when it starts, once when it ends.
 - Removed the filename from the elements, as images don't need them directly. "An image speaks a thousand words". However, need to find a solution for files and folders, as filenames are important in these cases.
 - Selection of items is now more pretty and in style with the current design (was difficult to do since i had to find out the hard way that a gridview pre-loads grid items with id = 0, while the first element in the grid also had id = 0... but works good now)
 - Added a yellow bottom bar with a tip. Was meant to show debug messages (like the old toasts in the previous commit) as fast as they come in, but I canceled this (for now). the idea was that tapping on the bar would show the log of messages that was shown in that bar. It would show tips and when selecting items it could show the filename and size
 - everything in the HomeActivity.onNavigationDrawerItemSelected is now moved to check for pin correctness
 - Directories.java is now DirectoryManager.java
 - Moved some IOnResult creations outside method calls
 - JSONArrayUnsorted.remove now returns an object containing the full result of the removal