Shopify/batman — pull request #305 by johnthethird (2012-01-14 23:50:22+00:00)
Title: Protect css class names with spaces to prevent problems with names that share character sequences. 

The check to see if a class already exists uses a simple indexOf which causes problems if one class name is a substring of another. Instead of breaking it up into an array split on a space char and checking that way, a simple space char for padding seems to take care of the issue.