Merge branch 'master' of https://github.com/mattermost/platform into mm-1696

Conflicts:
	web/react/components/setting_upload.jsx
	web/react/components/team_import_tab.jsx

web/sass-files/sass/partials/_sidebar--left.scss

@@ -124,7 +124,15 @@
 }
 
 .channel-loading-gif {
-    height:15px;
-    width:15px;
-    margin-top:2px;
+    height: 15px;
+    width: 15px;
+    margin-top: 2px;
+}
+
+.join-channel-loading-gif {
+    margin-top: 5px;
+    margin-left: 10px;
+    height: 25px;
+    width: 25px;
+
 }