[BUG] #50 Layers order issue when printing

When printing in LM master layers are not in the correct order, so for example a vector that in QGIS project is over a raster, in the print it is below. This does not happen in Lm 2.9

This regression is due to 58fdc583a0b9c4279f4c120159c543d8dfd4280f
Enhance print capabilities, in which we add the overview support.