Add more Clojure assignments.

Covers Accumulate, Binary Search Tree, Difference of Squares, Hexadecimal, and Largest Series Product.
Tweak test output for accumulate in Go
Use Fatalf in Go allergy test suite
Fix test output in Go anagram
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