Reformat all source with cargo fmt (#335)

Author: iceiix

README.md

@@ -97,7 +97,7 @@ There are a few basic ground-rules for contributors:
 1. **Non-master branches** ought to be used for ongoing work.
 1. **External API changes and significant modifications** ought to be subject to an **internal pull-request** to solicit feedback from other contributors.
 1. Internal pull-requests to solicit feedback are *encouraged* for any other non-trivial contribution but left to the discretion of the contributor.
-1. Contributors should attempt to adhere to the prevailing code-style.
+1. Contributors should attempt to adhere to the prevailing code-style. Please install and run [cargo fmt](https://github.com/rust-lang/rustfmt) before merging any changes.
 
 ### Changes to this arrangement