✨ use markdown-it for markdown previews
no issue
- replaces SimpleMDE's default `marked` rendering with `markdown-it`
- add ember-browserify and markdown-it plugins
no issue
- add ember-suave dependency
- upgrade grunt-jscs dependency
- add a new .jscsrc for the client's tests directory that extends from client's base .jscsrc
- separate client tests in Gruntfile jscs task so they pick up the test's .jscsrc
- standardize es6 usage across client
