message: Use a thumbnailed image for sender avatars
  Discord uses 128px square images, so 512px should be fine for most cases.
diff: @@ -167,7 +167,7 @@ export class DiscordBot {
  profile.displayname = profile.displayname || event.sender;
  if (profile.avatar_url) {
  const mxClient = this.bridge.getClientFactory().getClientAs();
  - profile.avatar_url = mxClient.mxcUrlToHttp(profile.avatar_url);
  + profile.avatar_url = mxClient.mxcUrlToHttp(profile.avatar_url, 512, 512, 'scale');
  }
  /* See issue #82
  const isMarkdown = (event.content.format === "org.matrix.custom.html");
  