creating desktop layout for search bar
modified search bar to adhere to mock breakpoints
Remove search field duplication.

adds navlist partial and responsive tests
replaces default bl search placeholder
Merge pull request #59 from sul-dlss/search-bar

Search bar layout
Merge pull request #81 from sul-dlss/search-placeholder

replaces default bl search placeholder
Add top-level hamburger menu to search bar with click area issue fix