DocumentUtils: Properly check the type of Document

* Check the correct portion of the uri to determine its type

Change-Id: I0a6fe2f1afe77f1990253621f537c396d8eead74
Signed-off-by: Brandon McAnsh <brandonm@matricom.net>
DocumentsUI: Differentiate USBs from SDcards

* Also remove need for context from getPath()

Change-Id: I92c3f54cbe414e7941f908f89995e4410af13cc7
Signed-off-by: Brandon McAnsh <brandonm@matricom.net>
DocumentsUI: Allow installation of apps from external storage

Change-Id: I50689eb61b66cefb091387aced185db55963ca51
Signed-off-by: Brandon McAnsh <brandonm@matricom.net>