EventPane layers broken after #3062

[ahocevar]

Pixel based panning (using Map::moveByPx) does not update EventPane layer positions. To move them, the Layer::moveByPx method (#3095) should be overridden.

For EventPane layers that have a dragPanObject, this is easy to fix, because the dragPanObject can also be moved by pixel deltas. For others, we need to investigate if the API provides a "move by pixel delta" method and use it. Those that don't have either will need to use Map::getCachedCenter() and call Layer::moveTo to move to the new center.

[ahocevar]

(In [11486]) make moveByPx work with EventPane layers (see #3096)

[ahocevar]

Fix included in latest patch for #3062.