Added Leaflet locate library for #51

This library (https://github.com/domoritz/leaflet-locatecontrol) is licensed under MIT license.
Using the Leaflet Locate library to locate the visitor's location

Closes #51

Signed-off-by: Fajran Iman Rusadi <fajran@gmail.com>
Put current location button above layers button
Also minify the locate control javascript file