Spending proposals did not have a winner attribute, instead winners
where calculated dynamically looking at votes
Removing this condition, so that we can see investment for the 2016
participatory budget which used spending proposals
The page should not show any headings which don't have any
winning investments. The "no content" message should only be
shown when there are no headings with investments to avoid an
otherwise blank page.
__Note:__ in the main @headings query, _both_ #includes and #joins
are needed to:
1. eager load all necessary data (#includes)
and
2. to perform an INNER JOIN on milestones to filter out investments
with no milestones (#joins).
