Upgrade haml lint

@monfresh Ready for review and merge.
For comments that span multiple lines, I put a pipe "|" (e.g. [see here](https://github.com/codeforamerica/ohana-web-search/compare/upgrade-haml-lint?expand=1#diff-6003393e0a41e700096fa14e44b05cc8R1)) on the first line so that all lines could be at the same indentation and haml-lint wouldn't complain about a space not appearing after the `-#` (which was stripped automatically by the whitespace stripping sublime plugin).