Pluggable spatial selector.

Perform a pluggable spatial selector and use it on a new query form `SpatialSelectorQueryForm`.

Implemented plugins:

* BBOX spatial selector
* Buffer spatial selector
* Polygon spatial selector
* Circle spatial selector
* Geocoder spatial selector

This commit also include:

* Minor fixes on WPS manager and procces
* Example configuration for the new query form on `mapcomposer/app/static/config/spatialSelectorQueryConfig.js`
Spatial selector translations.

Add tranlated strings for en/es/it languages
Spatial selector changes.

* Fixes layout bug on geocoder
* Add support for geocoder without WPS union
* Add some code docs.
Geocoder selector change.

Hide add and clean botton on simple selection of the geocoder.
Geocoder minor fixes

* Minor change on geocoder layout for simple selection
* Append `ignoreExtraDims` on wfs search combo
Geocoder fixes.

* Make WFS search combo output format configurable.
* Add option on the Geocoder to select different output format for the WFS search combo.
SpatialSelector fix

Remove old code on expand listener. Fix expand bug.
Spatial selectors plugins changes

* Include selection summary by default
* Change default styles
Remove deprecated plugin

Remove BBOXQueryForm plugin. We're going to use the SpatialSelectorQueryForm.
Update queryConfig.js

Include new plugin on the demo configuration.
Spatial Selector Query form changes

* Remove unused configuration on config examples
* Minor bug fix when no ROI selected --> use map extension
Merge pull request #333 from alediator/spatial_selector_plugin

Proposal #3: Pluggable SpatialSelector and SpatialSelectorQueryPanel