on that library need only adjust their mods' depends.txt files.  I've already
done this for flowers, junglegrass and poisonivy as included in this modpack,
so any mod that depends on one of *those* needs no changes at all.  No changes
to the API or any functionality.

leaving the plants folder as the primary API code and glue between them.  Any
of the three may be deleted to disable them if so desired.

guard radius around them to allow them to get a bit more dense.  Decreased the
perlin limit slightly, makes the biomes a little bigger.

fix the waterlily bug.  Reverted it.

This should, however, finally fix jungle grass turning into dry shrubs when it
shouldn't, and the list of growing surfaces seems to work properly now.  Will
fix the waterlily bug later.

Updated API.txt accordingly.

needed to allow old mods to use the new function without changes.

spawn, so plants places on e.g. cobble or a flower poit don't change.