Fixes non-passing test

Terminology popup was not being clicked in test, as the JS event used
is a mousedown event, not a click event. This commit fixes the test to
trigger a mousedown event.
Updates styles

Updates to CSS:
- Adjust margin to inside search form box
- Adjust detail view sidebar styles to put icons in an aligned column
- removes italics from agency name style
Merge pull request #202 from codeforamerica/floating-header

Floating header