Only show Mount USB storage if UMS possible

In the mounts and storage menu:
* Reduce the complexity of if/elses for /data/media and UMS specific
  menu entries with a simple struct
* Only show UMS mount option if vold managed volumes are available and
  usb-otg is not in use. Vold does not have any mechanism to determine
  if a managed volume is usb-otg, so we have to rely on string
  comparison to the volume label. "usbdisk" is by far the most common
  label, so this should cover most devices just fine.

Change-Id: I8a203a614e1c603c32a06b1afb77834cc4cd51ce
Version 6.0.5.0

Notable changes since 6.0.4.9:
* Segfault fixes for command line nandroid backup/restore
* Optimizations to progress thread so it doesn't get overloaded with
  screen updates (this significantly improves backup/restore speed)
* Fixes for command line nandroid backups of vold volumes
* Correctly update background image for errors and finished processes
* Allow selective restore of more than one partition at a time
* New MD5 calculator only verifies checksums of partition(s) selected
  for restore and warns you when files or checksums are not found
* New touch code supports a wider variety of devices for swipe control
  and virtual (capacative touch) keys are now supported
* Only show Mount USB storage option if possible

Change-Id: I813dce9d31ce2aa445a512026a210a558cab39e6