Updates icon

External link icon for directions had incorrect unicode character. This
commit fixes that.
Adds initial floating header manager JS

Adds initial script for managing the fixed positioning of the header
when
scrolling the page.
Merge branch 'master' into develop
Updates mapbox static map tile URL

Map tile was outdated. This updates the URL to a working map. This is a
temporary solution as this should really use a mapbox key for
retrieving maps. However, detail views a likely to replace static maps
with regular maps the can be zoomed, panned, etc.
Merges `master`
Merge branch 'poltergeist-integration' into develop
Fixes header-manager JS script path post-merge

Poltergeist-integration branch was merged, but header-manager JS script
path needed changing.
Adds missing parameter to search-init script
Fixes results header when scrolling

When scrolling results header is fixed by adding a class that fixes its
position, keeping it at the top of the browser window.
Merge branch 'master' into develop
Moves header manager initialization to ajax-search module

In order to re-initialize the header manager, this commit moves that
module to the ajax-search module, which initializes it on first load
and after successful ajax queries.
Simplifies floating header vertical offset

Floating header vertical offset scroll height (the scroll distance at
which the header starts to float) was being calculated based on the
position of the floating header. This commit changes that to the height
of the content header above it, which simplifies the calculation.
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