grrs-lazy

A simple search utility, based on the rust cli-wg tutorial: https://rust-lang-nursery.github.io/cli-wg/tutorial/

It has a few differences from the final grrs built in the tutorial:

1. Separated out find_matches in src/lib.rs.
2. Using std::io::BufReader instead of std::fs::read_to_string, so that we avoid loading all the content from a file in memory.
3. Dealing with iterators in find_matches, so that the processing is done in a lazy stream.