Use minified version for leaflet resources

[amitness]

We can use leaflet.min.js and leaflet.min.css provided by their site instead of leaflet.js and leaflet.css.

[sagargg-zz]

i did some modification on leaflet thats why non minify is used. but will fix later.

[sagargg-zz]

now it is fixed. but css remains non minified version for future update.