the unified headers flag is now default on the make_standalong_toolchain.py script for Android rust cross compilation. The flag is now removed from the article in order to keep the information relevant and useful
* Add blog post for Rust on Android
* update README with link to new post
* Address review comments @rnewman @jwalker
* Update post to make copying cargo-config.toml to the .cargo directory non-optional
* Address review comments @jwalker