Edited existing textures and added new from "along_shore".
Waterlilies and seaweed spawn ongen.

my flowers mod, and renames it to flowers_plus.

backward-compat aliases, in preparation for a subset of these flowers
being added to "common".

texture files to their respective components' folders (<f>/textures).  Also,
began working on extending the API for the growing code to allow for checking
for the height of a node.  Poisonivy is the only component that uses it for
now; this is more intended to be used with nature pack eventually.

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.