Merge branch 'develop' of https://github.com/wordpress-mobile/WordPress-Android into feature/2968-stats-widget

Conflicts:
	WordPress/src/main/java/org/wordpress/android/ui/accounts/SignInFragment.java

Author: daniloercoli

WordPressAnalytics/src/main/java/org/wordpress/android/analytics/AnalyticsTrackerMixpanel.java

@@ -266,6 +266,10 @@ private AnalyticsTrackerMixpanelInstructionsForStat instructionsForStat(
                 instructions = AnalyticsTrackerMixpanelInstructionsForStat.
                         mixpanelInstructionsForEventName("Application Closed");
                 break;
+            case APPLICATION_UPGRADED:
+                instructions = AnalyticsTrackerMixpanelInstructionsForStat.
+                        mixpanelInstructionsForEventName("Application Upgraded");
+                break;
             case THEMES_ACCESSED_THEMES_BROWSER:
                 instructions = AnalyticsTrackerMixpanelInstructionsForStat.
                         mixpanelInstructionsForEventName("Themes - Accessed Theme Browser");