Cider REPL

When using Cider you want your REPL to use Cider's middlewares so stack traces in Emacs are nicely formatted, etc. (You'll need to use the latest Cider, rather than 0.8.2 stable.) Here's how to do it:

1. Make sure your version of boot is recent by running boot -u.**

2. Make your ~/.profile.boot or build.boot look like the following. ~/.profile.boot is preferred so that you don't force other people to default to Cider, even though they really should.

   (require 'boot.repl)
   (swap! boot.repl/*default-dependencies*
          concat [[cider/cider-nrepl "0.8.2"]])
   
   (swap! boot.repl/*default-middleware*
          conj 'cider.nrepl/cider-middleware)

   NOTE: Make sure to have an ' (apostrophe) before [[cider/cider-nrepl "0.8.2"]]. (If it's not shown here that means Github's syntax highlighting is still broken.)

3. Run REPL as usual with boot repl.**

You can find more documentation in commit 1a765793