MOC saving improvements, Mac app activation, loading overlay, USM update.

[MOVED]     iOS code from MPAppDelegate_Shared to MPiOSAppDelegate.
[FIXED]     Perform MOC saving in MOC perform blocks.
[FIXED]     Mac: Activate app when showing password window and not active.
[FIXED]     Hide overlay while corruption dialog is up.
[FIXED]     Hide corruption dialog when reloading store.

External/Crashlytics.framework/Versions/A/Headers/Crashlytics.h

@@ -170,6 +170,16 @@ OBJC_EXTERN void CLSNSLog(NSString *format, ...) NS_FORMAT_FUNCTION(1,2);
  **/
 @property (nonatomic, readonly) NSDate *crashedOnDate;
 
+/**
+ * Returns the os version that the application crashed on.
+ **/
+@property (nonatomic, readonly) NSString *OSVersion;
+
+/**
+ * Returns the os build version that the application crashed on.
+ **/
+@property (nonatomic, readonly) NSString *OSBuildVersion;
+
 @end
 
 /**