only plant sapling if block is air.  
attempt to do work on a work-tick even if a rescan is triggered first  
save out blocksToChop list to nbt for foresty farm  
save out workRescanDelay to nbt for forestry farm  
if bonemeal grows a tree, add it to blocksToChop immediately  
when scanning for trees, don't re-scan a base block that is already in
the blocksToChop set, should eliminate rescans of entire trees