Custom tabs are now used for login and links on account pages, with a fallback to the default browser if not supported.

Also, fixes crashes when entering tag and threads due to me forgetting to implement the interfaces required by the code that removes posts from timelines when blocking/muting.

Also fixes a small bug where for mentions of users from other instances, clicking on the mention would open the profile in the browser instead of in-app.

app/src/main/java/com/keylesspalace/tusky/entity/Status.java

@@ -146,5 +146,8 @@ public class Status {
 
         @SerializedName("acct")
         public String username;
+
+        @SerializedName("username")
+        public String localUsername;
     }
 }