Remove url-crawler as it's gone away

README.md

@@ -1260,8 +1260,6 @@ See also [Are we game yet?](https://arewegameyet.rs)
   * [mattnenterprise/rust-ftp](https://github.com/mattnenterprise/rust-ftp) — an [FTP](https://en.wikipedia.org/wiki/File_Transfer_Protocol) client for Rust [![build badge](https://api.travis-ci.org/mattnenterprise/rust-ftp.svg?branch=master)](https://travis-ci.org/mattnenterprise/rust-ftp)
 * gRPC
   * [tikv/grpc-rs](https://github.com/tikv/grpc-rs) — The gRPC library for Rust built on C Core library and futures [![Build Status](https://api.travis-ci.org/tikv/grpc-rs.svg?branch=master)](https://travis-ci.org/tikv/grpc-rs)
-* HTTP
-  * [pop-os/url-crawler](https://github.com/pop-os/url-crawler) — A configurable parallel web crawler, designed to crawl a website for content.
 * IPNetwork
   * [achanda/ipnetwork](https://github.com/achanda/ipnetwork) — A library to work with IP networks in pure Rust [![build badge](https://api.travis-ci.org/achanda/ipnetwork.svg?branch=master)](https://travis-ci.org/achanda/ipnetwork)
   * [candrew/netsim](https://github.com/canndrew/netsim) — A Rust library for network simulation and testing [![build badge](https://api.travis-ci.org/canndrew/netsim.svg?branch=master)](https://travis-ci.org/canndrew/netsim)