Show the start of the search query/address/POI in the search bar

Repositions the text in the search bar to show the start of the query when search is executed or an auto-complete option is selected. Uses `EditText#setSelection(0)` to move the cursor and reposition the text.
Merge pull request #309 from mapzen/chuck/show-start-of-query-text

Show the start of the search query/address/POI in the search bar