Dev import wms

Add a component which permits to add a WMS layer.  

You choose a WMS server in the list or you type your own WMS URL then tap connect.

The list of available layer appears on the table.
 
In the table,  onmouseover event, the layer is added to the map then the map zoom to fit  its extent  (the extent is calculated taking into account the minScale value, if defined) .
Onmouseleave event the layer is removed from the map.

If you select a layer the description is blocked so you can scroll it.

If you click the button add_layer, the layer selected is definitively added to the map. 
 


Tested on chrome and ie9.


To fix:

- Private method and constants definitons to calculate the current map scale  #197 



Links available:
http://mf-geoadmin30t.bgdi.admin.ch/branch/dev_import_wms/src/