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
MAPSTORE-9 add qr code support for maps
MAPSTORE-9 fixed compatibility with IE8 and previous
Feature grid improvements

* Add `exportFormats` and `exportFormatsConfig` options to this widget.
* Add images and styles for the new exports
* Minor fix on Circle spatial selector.

You can test it adding the feature grid with this configuration:

```
	    {
		  "ptype": "gxp_featuregrid",
		  "featureManager": "featuremanager",
		  "outputConfig": {
			  "id": "featuregrid",
			  "title": "Features"
		  },
		  "outputTarget": "south",
		  "exportFormats": ["CSV","shape-zip","excel", "excel2007"]
	    }
```
MAPSTORE-11 add qrcode in home page
Feature grid improvements

* Export action as window by default
* Es/en translations for new options
Merge branch 'master' of github.com:geosolutions-it/MapStore
MAPSTORE-11 site configurations and fixes
Merge pull request #336 from alediator/download_formats

Feature grid improvements