Fixed links

For example, "latest release" linked to http://exercism.io/help/github.com/exercism/cli/releases/latest
Only use buttons for submissions with reviews or comments

The rationale being that some people iteratively send in their
exercises, without awaiting comments. This makes it really hard to
judge if you're looking at submission 8 whether a whole discussion has
already been had, or whether no discussion has been had at all.
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
Fix utterly ridiculous bug in stats
Add list ops README

(Forgot to add it in the ocaml list-ops commit)
Add elixir list-ops
Remove obsolete elixir accumulate and strain

These exercises have been replaced by list-ops
Merge pull request #1254 from pminten/ocaml-list-ops-readme

Add list ops README
Add list-ops back into OCaml
Add specs to linked-list_test.spec.js 

Flesh out the linked-list spec in JavaScript:
- Change Deque to LinkedList
- Add specs to test count() and delete() functions.
Update test name in javascript phone-number. Fixes #1259.
Add link to language list on new homepage