Added the searching ability with distance and Tags

Changes made to users.js, package.json, content.js, index.js, session.js
and Userdashboard.
users.js getTrucksByTags, searchTrucksForUserWithDistance, getTrucks.
package.json added dependency 'google-distance-matrix'.
content.js modification to displayUserDashboardPage function.
session.js added searchTrucksForUser function.
userDashboard added infoWindow line for URL and Search button.