[BUGFIX] #64 OpenCycleMap base layer bug

Bug while using OSM Cyclemap among other baselayers
[BUGFIX] #65 Print - wrong rectangle proportions if many composers

To reproduce
* create a project with 2 composers, with a map of different proportion
* in LWC, use the print menu with the 2nd composer. At start, the drawn rectangle has the correct proportion.
* Change the chosen scale in the combobox : the rectangle takes the proportions of the 1st composer