Fix undefined quote in Item:build_return_groups
Make custom_display_name work for project-level items

This lets users customize the way module/topic/file/etc names are shown.
Support used-defined keywords (in prettified code).
Merge pull request #183 from mikz/patch-1

Fix undefined quote in Item:build_return_groups
Merge pull request #184 from mooffie/custom_display_name_for_project_level_items_too

Make custom_display_name work for project-level items
Merge pull request #185 from mooffie/user_keywords

Support used-defined keywords (in prettified code).