Improve search and left nav-bar

[tasha-m-k]

Comments from Ben:

• The search doesn’t seem very good (terms like push, generate don’t result in any hits, for example).
• The left-hand nav bar goes off the bottom of the page for me, but doesn’t scroll.

We might not be able to do anything about the search, but we can investigate, and we should be able to do something about the nav bar.