Add WMS thumbnail maker panel to editor.

This panel is added to the popup which allows to add thumbnail by URL or Upload.
A new mode is added providing a map with the background layer and all WMS layers registered
in the metadata record. User can choose a layout, a scale and an area of interest
in order to print the map in PNG format and attach it to the current metadata record.

Changes:
* Update MapFish print to 2.0 version
* Move MapFish print module configuration and resources file to WEB-INF/config-print (instead of webapp root folder)
* Add layout and PDF template for printing thumbnail
Merge remote-tracking branch 'upstream/develop' into feature/wms-thumbnail-maker
Move to print-lib 2.0.0.
Merge remote-tracking branch 'upstream/develop' into feature/wms-thumbnail-maker
Add rotation parameter for PDF in landscape mode.
Add warning message if no WMS layer found for generating thumbnail.
Merge pull request #426 from fxprunayre/feature/wms-thumbnail-maker

WMS thumbnail maker panel