Updated options_form(), options_form_validate() and options_form_submit() methods with proper signature so we can alter object in class method properly like in openlayers_source_osm. If url options is empty, remove it from options.

- Remove CTools warning about missing files by adding the 'file' key to the array defining the plugin.

- Complete rewrite of the module.
- OpenLayers 3 JS Library
- New user interface, options...
- Many things are broken and needs to be worked on, but at least, we have something to start.