Create Version of Plugin Without Font Awesome Dependency

[pmacMaps]

These commits represent a proposed branch of this project that removes the Font Awesome dependency.

The plugin uses an img element, which is provided in the dist folder, but is set in the constructor options. This allows the user to decide where to store the referenced img element.

Changes:

-- Use img element instead of i element. -- Remove Font Awesome Dependency. -- Update Leaflet.js and jQuery in example. -- Remove Bootstrap in example. -- Add css rule so "legend" element shows above map.