Move even more vold commands over to Binder.

This moves fstrim, obb and appfuse commands over to the new Binder
interface.  This change also separates creating/destroying and
mounting/unmounting of OBB volumes, which means they finally flow
nicely into the modern VolumeInfo/VolumeBase design.

We now generate unique identifiers for all OBB volumes, instead of
using a shady MD5 hash.

Change all "loop" and "dm" devices to tag the kernel resources with
a vold-specific prefix so that we can clean them up if vold crashes;
there are new destroyAll() methods that handle this cleanup.

Move appfuse mounting/unmounting into VolumeManager so it can be
shared.  Move various model objects into a separate directory to
tidy things up.

Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Bug: 13758960
Change-Id: I7294e32b3fb6efe07cb3b77bd20166e70b66958f
diff --git a/Loop.h b/Loop.h
index 5d8f427..e3ad239 100644
--- a/Loop.h
+++ b/Loop.h
@@ -32,7 +32,7 @@
     static int create(const char *id, const char *loopFile, char *loopDeviceBuffer, size_t len);
     static int create(const std::string& file, std::string& out_device);
     static int destroyByDevice(const char *loopDevice);
-    static int destroyByFile(const char *loopFile);
+    static int destroyAll();
     static int createImageFile(const char *file, unsigned long numSectors);
     static int resizeImageFile(const char *file, unsigned long numSectors);