File resolution issues when importing + defining base_path

[crowdagger]

Let's say you have the following structure:

• common.book
• images/
  • foo.png
• 01/
  • 01.book
• 02/
  • 02.book

In common.book, you want to define the base path for images to images/:

resources.base_path.images: images/

You also want to specify an icon for html rendering:

html.icon: foo.png

But now, when you run crowbook 01/01.book you get an error: "Could not find file '01/../images/../foo.png'"

This is because "../" is concatenated to html.icon, which would be the thing to do if resources.base_bath was not defined, but in this case it causes a problem.