Add basic "search" to project-specific issue views

A proposal:

Would also save me a lot of clicking. The advanced search is great and all if you need to get really fine-grained on multiple criteria, but often all you really want to do is filter the listing by a particular keyword. So why not make a search box immediately available when you get to this page?

We could potentially expose this filter on other pages too, but some of them are quite wide.