Add setScreenOrientation to BaseUiAutomation class

This allows workloads to be launched in a pre-determined orientation not the orientation of the physical device itself.

Updated the productivity workloads to take advantage of this new facility.

wlauto/workloads/gmail/uiauto/src/com/arm/wlauto/uiauto/UiAutomation.java

@@ -39,6 +39,8 @@ public class UiAutomation extends UxPerfUiAutomation {
     public void runUiAutomation() throws Exception {
         parameters = getParams();
 
+        setScreenOrientation(ScreenOrientation.NATURAL);
+
         clearFirstRunDialogues();
 
         clickNewMail();