Continue removing ExtensionPoint code. Start fixing build errors.

Mac/Preferences/PreferencesWindowController.swift

@@ -39,9 +39,6 @@ private struct ToolbarItemIdentifier {
 		specs += [PreferencesToolbarItemSpec(identifierRawValue: ToolbarItemIdentifier.Accounts,
 											 name: NSLocalizedString("button.title.accounts", comment: "Account"),
 											 image: AppAssets.preferencesToolbarAccountsImage)]
-		specs += [PreferencesToolbarItemSpec(identifierRawValue: ToolbarItemIdentifier.Extensions,
-											 name: NSLocalizedString("button.title.extensions", comment: "Extensions"),
-											 image: AppAssets.preferencesToolbarExtensionsImage)]
 
 		// Omit the Advanced Preferences for now because the Software Update related functionality is
 		// forbidden/non-applicable, and we can rely upon Apple to some extent for crash reports. We

Mac/Resources/Assets.xcassets/MicroblogIcon.imageset/Contents.json

@@ -0,0 +1,25 @@
+{
+  "images" : [
+    {
+      "filename" : "micro.blog.24.png",
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "micro.blog.48.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "properties" : {
+    "template-rendering-intent" : "original"
+  }
+}