[BUG] #32 Reverse order in popup

In case of multiple elements is on a same point, the order in which the
different elements seems reversed: on the map higher #recno are on top,
whereas on the popup they are at the bottom.

LizMap will revert the order if the GetFeatureInfo requesting HTML
output format.
OpenLayers: Update to 2.13.1

This commit is done to update OpenLayers 2 to the last available
version.
OpenLayers: update edition for OL 2.13.1
[Enhancement] #33 Add IGN Geoportail and GMap geocoding - funded by Pays de Pontivy

The administrator must be able to choose the geocoder that he would like the web user will use.

The OpenStreetMap geocoder, Nominatom, may already be selected.
The GMap geocoder has to be used with Google baselayer to respect the CGU.
The IGN Géoportail geocoder is for french users.
[Enhancement] #31 empty baselayer

It would be nice to have an option to add an "empty" base layer, that does not show anything.
[enhancement] Optionnal direct access for external WMS layers - #34