Use shell expansion and add format task to Makefile

The README mentions a `make format` task that runs `go fmt` on the entire project, but it doesn't actually exist. This PR adds that task. It also fixes a bug in which the dependencies were not actually being expanded for the `go get` command because no shell command was run in resolution.

Additionally, it adds the new `format` task to the build task and silences some of the large, ugly `echo` output.