Move copy for home page panel into en.yml

Adds some placeholder marketing copy.
More marketing copy for the home page
Adds validation to accept only the values given in the array
Adding spec to verify presence of category field in Recipe
Adding radio buttons against each recipe category
Adding integration specs for New and Edit recipe page
Adding category to recipe#show page.
Removing whitespace
Fixing bug with category values against each recipe and tidying up
Darkens carousel buttons, home and classes panel backgrounds
CSS transitions on mouse overs
Refine the styling of buttons on the recipe carousel
Update font-awesome and tweak the fonts on the recipe carousel
Further tweaks to the carousel buttons
Merge branch 'master' of aloysius.unfuddle.com:aloysius/mk
Updates font-awesome-rails gem to fix missing carousel button icons
Applies default letter spacing to the whole site
Adds similar recipe list to the Recipe#show page

This is based on a very simple rule for now. It displays the first three
recipes that are of the same category
Adds basic subscription welcome mailer

Also configures sendgrid for running in production
Removed redundant test directory