display: Add rotation angle interface

display: Add rotation angle interface

rotation angle means "physical display" direction.
Clients can rotate display or check current display angle.

dbus method:
dbus_getrotationangle
  path: "/Org/Tizen/System/DeviceD/Display"
  interace: "org.tizen.system.deviced.display"
  member: "GetRotationAngle"
  paremeter: "(i)", display index to get rotation angle.
  return: "(ii)", 0 on success, negative on error.
	enum display rotation angle to get.

dbus_setrotationangle
  path: "/Org/Tizen/System/DeviceD/Display"
  interace: "org.tizen.system.deviced.display"
  member: "SetRotationAngle"
  paremeter: "(iii)", display index to set rotation angle.
		enum display rotation angle to set.
		enum display rotation direction.
  return: "(i)", 0 on success, negative on error.

Change-Id: I792dd4d68034d511443c3c09c5b37bea220bce81
Signed-off-by: TaeminYeom <taemin.yeom@samsung.com>