style: rustfmt everything

This is why I was so intent on clearing the PR queue. This will
effectively invalidate all existing patches, so I wanted to start from a
clean slate.

We do make one little tweak: we put the default type definitions in
their own file and tell rustfmt to keep its grubby mits off of it. We
also sort it lexicographically and hopefully will enforce that from here
on.

grep-regex/src/util.rs

@@ -1,8 +1,8 @@
 /// Converts an arbitrary sequence of bytes to a literal suitable for building
 /// a regular expression.
 pub fn bytes_to_regex(bs: &[u8]) -> String {
-    use std::fmt::Write;
     use regex_syntax::is_meta_character;
+    use std::fmt::Write;
 
     let mut s = String::with_capacity(bs.len());
     for &b in bs {