Fix crash when trying to route null link

app/src/main/java/com/commit451/gitlab/navigation/RoutingNavigator.java

 package com.commit451.gitlab.navigation;
 import android.net.Uri;
+import android.support.annotation.Nullable;
 /**
  * Interface called when routing in the Routing activity
@@ -12,5 +13,5 @@ public interface RoutingNavigator {
     void onRouteToProject(String namespace, String projectId);
     void onRouteToBuild(String projectNamespace, String projectName, String buildNumber);
     void onRouteToMilestone(String projectNamespace, String projectName, String milestoneNumber);
-    void onRouteUnknown(Uri uri);
+    void onRouteUnknown(@Nullable Uri uri);
 }

app/src/main/java/com/commit451/gitlab/navigation/RoutingRouter.java

 package com.commit451.gitlab.navigation;
 import android.net.Uri;
+import android.support.annotation.Nullable;
 /**
  * Routes things. Could probably be better if it used regex. Maybe one day
@@ -13,7 +14,11 @@ public class RoutingRouter {
         mNavigator = routingNavigator;
     }
-    public void route(Uri link) {
+    public void route(@Nullable Uri link) {
+        if (link == null) {
+            mNavigator.onRouteUnknown(null);
+            return;
+        }
         if (link.getPath().contains("issues")) {
             if (link.getLastPathSegment().equals("issues")) {
                 //this means it was just a link to something like

app/src/main/java/com/commit451/gitlab/widget/AccountViewHolder.java

@@ -7,11 +7,11 @@ import android.widget.ImageView;
 import android.widget.TextView;
 import com.alexgwyn.recyclerviewsquire.TypedViewHolder;
-import com.commit451.gitlab.App;
 import com.commit451.gitlab.R;
 import com.commit451.gitlab.model.Account;
 import com.commit451.gitlab.transformation.CircleTransformation;
 import com.commit451.gitlab.util.ImageUtil;
+import com.squareup.picasso.Picasso;
 import butterknife.BindView;
 import butterknife.ButterKnife;
@@ -41,7 +41,7 @@ public class AccountViewHolder extends TypedViewHolder<Account> {
         mServerView.setText(item.getServerUrl().toString());
         mUsernameView.setText(item.getUser().getUsername());
-        App.instance().getPicasso()
+        Picasso.with(getContext())
                 .load(ImageUtil.getAvatarUrl(item.getUser(), itemView.getResources().getDimensionPixelSize(R.dimen.user_list_image_size)))
                 .transform(new CircleTransformation())
                 .into(mImageView);