We enable the button when the map has finished loading to prevent the preview map to be empty.
Advances #83135: added footer and header for the pdf, improved validation, removed logo data uri (substituted by logo url), we create the legend manually instead of depending on mapfish for better results.
Merge branch '8.5-SNAPSHOT' of github.com:Emergya/sir-geoexplorer-base-js into 8.5-SNAPSHOT-83135
Merge pull request #136 from luisromangz/8.5-SNAPSHOT-83135

8.5 snapshot 83135