Add more Clojure assignments.

Covers Accumulate, Binary Search Tree, Difference of Squares, Hexadecimal, and Largest Series Product.
Update the Installing Elixir instructions on OS X.

Simplify the instructions for installing erlang and elixir with homebrew.

Fixes #1243.
Update nit count on nit delete - fixes #1240
Added foreman to the Gemfile.
Merge pull request #1246 from ebautistabar/add_foreman_to_gemfile

Added foreman to the Gemfile.
Merge pull request #1242 from geofflane/clojure_add-missing-assignments

Add more Clojure assignments
Merge pull request #1244 from brettchalupa/update-erlang-os-x-installation-instructions

Update the Installing Elixir instructions on OS X.
Merge pull request #1245 from ebautistabar/update_nit_count_on_delete

Update nit count on nit delete - fixes #1240
Fix N+1’s on viewing submission. Include user and comments
Merge pull request #1247 from mscoutermarsh/n_plus_1s

Fix N+1’s on viewing submission.
Fixed links

For example, "latest release" linked to http://exercism.io/help/github.com/exercism/cli/releases/latest
Updated nit deletion test
Add ocaml list-ops exercise
Merge pull request #1249 from spraints/patch-1

Fixed links in help/cli
Merge pull request #1251 from ebautistabar/update_nit_count_on_delete

Updated nit deletion test
Merge pull request #1252 from pminten/ocaml-list-ops

Add ocaml list-ops exercise
Remove list-ops from OCaml track

The meta-data is missing, so we can't serve a README.
Ruby Proverb added test to avoid someone hardcoding the required lyrics.
Merge pull request #1253 from RichardWigley/master

Ruby Proverb added test to avoid someone hardcoding the required lyrics.
Make stats accessible