Listing suggestions

Closes issue #30.
suggestions/index is not being used. Suggestions get displayed in the each loop in the initiative template since suggestions belong to initiatives. AFAIK (but I don't know much), it will be possible to define viewing controls etc in the suggestions controller as usual, then in the initiative template each loop you can use itemController to tell the template to use the suggestions controller instead of the initiatve controller. At least, this is how we did it for listing issues. WDYT?