Release version 0.7.9

Release version 0.7.9

Changes:
 - Add a step for recovering ReadonlyUpdateInstall mode
 - Add StepPrivilegeCompatibility at RecoverySteps
 - Add StepPrivilegeCompatibility at ReadonlyUpdateUninstallSteps
 - Replace StepPrivilegeCompatibility with StepRecoverPrivilegeCompatibility
 - Fix RecoverySteps of hybrid backend
 - Remove unnecessary step
 - Set nodisplay attribute of widget application as manifest value

Change-Id: I8042b5f4a817454e02452f63eb50d5652d940916
Signed-off-by: Sangyoon Jang <jeremy.jang@samsung.com>