Added use of $ for bash commands to readme & contributing guide
Standardized bash $ format on examples in readme/contributing
Standardized bash $ syntax on several guides.
Added links to the sample code files.
Remove legacy source directory which is not used by nanoc
Added new filter to make TODO content blocks easier to spot
Started work on message basics
Fix message
A few spelling corrections, one minor sample code fix.
Merge branch 'master' of github.com:spree/spree-guides

Conflicts:
	content/integration/message_basics.md
Add --- filter for adding filenames to code examples
More progress on message basics
Style section title icons
Fixed capitalization error.
Converted all of the guides to the new TODO format.
Corrections to the block markup convention explanation
Mostly spelling and style changes to the message basics guide.
added method call inside hubspot endpoint
Modified endpoint_creation tutorial to use for notification messages
Created a placeholder page for fulfillment integration tutorial