Version 3

Removal of setOption method on the control
getTile is now getBlobByKey
openTilesDataBase is now an export function to get whole idb database
New control option alwaysDownload, if false, the control will not redownload tiles already in the db (and the savetile* event do not fire)

Version 4

Changed arguments of getStoredTilesAsJson: send an object with tilesize instead of the full layer