Spectre migration updates.

[ADDED]     Migration prompt to sign-in screen.
[FIXED]     Spectre Apple ID.

platform-darwin/Source/iOS/MPUsersViewController.m

@@ -100,6 +100,7 @@ typedef NS_ENUM( NSUInteger, MPActiveUserState ) {
 
     [self registerObservers];
     [self reloadUsers];
+    [self updateSpectreAlerts];
 
     [self.marqueeTipTimer invalidate];
     self.marqueeTipTimer = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector( firedMarqueeTimer: )
@@ -660,6 +661,7 @@ referenceSizeForFooterInSection:(NSInteger)section {
     PearlAddNotificationObserver( UIApplicationWillEnterForegroundNotification, nil, [NSOperationQueue mainQueue],
             ^(MPUsersViewController *self, NSNotification *note) {
                 [self reloadUsers];
+                [self updateSpectreAlerts];
             } );
     PearlAddNotificationObserver( UIApplicationDidBecomeActiveNotification, nil, [NSOperationQueue mainQueue],
             ^(MPUsersViewController *self, NSNotification *note) {
@@ -726,6 +728,17 @@ referenceSizeForFooterInSection:(NSInteger)section {
     }];
 }
 
+- (void)updateSpectreAlerts {
+
+    BOOL spectreInstalled = [UIApp canOpenURL:[[NSURL alloc] initWithString:@"spectre:"]];
+    if (spectreInstalled) {
+        self.spectreInstallAlert.visible = NO;
+    }
+    else {
+        self.spectreInstallAlert.visible = [MPiOSAppDelegate get].spectreViewController != nil;
+    }
+}
+
 #pragma mark - NSFetchedResultsControllerDelegate
 
 - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
@@ -907,4 +920,9 @@ referenceSizeForFooterInSection:(NSInteger)section {
         ++[self selectedAvatar].avatar;
 }
 
+- (IBAction)upgradeSpectre:(UIButton *)sender {
+
+    [[MPiOSAppDelegate get] migrateFor:nil];
+}
+
 @end