[FEATURE] #16 WFS - add appropriate methods to allow Lizmap to act as a complet proxy

The commit ac1e3aa06f5f99a52c500eef27dd01ebe1ef7028 added
DescribeFeatureType support
This one adds the capability to POST XML request to QGIS-Server.
It's allow edition with Web Feature Service Transaction.
[DEBUG] Editable data list has 2 modal-header

The second modal-header has to ba a modal-body
[DEBUG] Test keyColumn and valueColumn in combobox

When constructing combobox, it's necessary to test the properties
keyColumn and valueColumn
[DEBUG] Removing duplicate scales

Verifying that the scales list does not contain duplicate values.
[DEBUG] Add date type to edition for save NULL
[DEBUG] Array.indexOf not supported by IE

Array.indexOf is not supported by Internet Explorer, replaced by
$.inArray
BUG introduced by commit 4e6d64278c32ad9729936de64b7edc71c7aade56
[DEBUG] Add WFS GetFeature OUTPUTFORMAT param

If there is no OUTPUTFORMAT param in the WFS GetFeature request, LizMap
force it to GML2
IT translations
Add NULL for float data type
[DEBUG] #41 Locating (location by layer) seems to have stopped to work in latest revisions

The bug comes from that LizMap forced the OUTPUTFORMAT to GML2 instead
to stay to GeoJSON.
[FEATURE] #42 Enhance print capabilities

Add overview in print
Add the capability to update labels
Change Openlayers files rights