SetupWizard: Add option to apply default theme if one exists

* A bunch of code cleanup/refactoring to make this work

Change-Id: I059fb5fa5bcd7dd8821e993218a320554f10a314

src/com/cyanogenmod/setupwizard/setup/CMSetupWizardData.java

@@ -35,7 +35,7 @@ public class CMSetupWizardData extends AbstractSetupData {
     private boolean mTimeSet = false;
     private boolean mTimeZoneSet = false;
 
-    public CMSetupWizardData(SetupWizardActivity context) {
+    public CMSetupWizardData(Context context) {
         super(context);
     }