Do not includes pages not in matched files in Sassdown.config.tree, and set the isFile property on file tree nodes so they're easier to work with in templates.
Enables the use of Handlebars Helpers in the template.
Merge pull request #61 from EvilOatmeal/45-tree_includes_pages_not_in_matched_files

Do not includes pages not in matched files in Sassdown.config.tree
Merge pull request #62 from EvilOatmeal/add-handlebars-helpers

Enables Handlebars Helpers in the template