rename ImageFormat#thinProvisioned -> ImageFormat#supportThinProvisioning
Add preallocation column to the volumes table
add a test case to test qemu-img with preallocation option
add provisionType parameter to createDiskFromTemplate method
fix VolumeObject class to reflect the change in Volume class
add "ProvisioningType" member to DiskProfile
add 'ProvisioningType' member to VolumeObjectTO
make provisioningType constructor parameter mandatory in VolumeVO class
define Preallocation enum
set default provisioning type sparse temporarilly.
set preallocation option as qemu-img option
fix allocateTemplatedVolume to meet qcow2 constraint

backing file option cannot be used with preallocation=metadata
make DataDisk sparse ready
set provisioningType in allocVolume method
refactor LibVirtStorageAdaptor#createPhysicalDisk
replace libvirt by qemu-img for volume creation

to support preallocation option
refactor LibvirtStorageAdoptor#createDiskFromTemplate to shape up
correct the wrong physical disk directory pass
change qemu-img info output format to get acurate disk size

change output format from human to json
Feature: add sparse mode support (hard coding)