[typo] replaced newline to separate docs/code
added first draft of ql:shipment:confirm message
added po:confirm and po:received messages
Fix typo 'contains' -> 'contain' in integration/consuming
Add 'call to action' on the developer index
Fix GS tutorial, added Rails version ddependency and added link to imagemagick.org for windows/unix users

Fixes #148
Add integrator banner
Placeholder JSON for the QL integration
added purchase_order:transmit message
added shipping_order_transmit
added purchase_order_received message
added shipment:confirm and document:download messages
removed extra message name
Placeholder for new custom attributes guide
Changed title text for Integration Guide
fix small typo
Make navigation wider to accommodate new 'User' link
Add placeholder content for user guides
Add user guides link to home page navigation
Add some user placeholder pages