Fixes #139 - positions search area

Search area could be moved to the right. This commit updates the styles
to:
- provide even padding around all search elements.
- evenly distribute the filters
- increase height of header by 1px to remove 1px gap between search
header and content.
Merge pull request #145 from codeforamerica/139-search-filter-position

Fixes #139 - positions search area