+ tree stuff. ^ evaluate_affectMaterial()

I'm getting some stuff done with trees.
currently, you can place a tree_base and it will spawn tree_trunk above it.
the tree_trunk will keep going until it spawns a tree_trunk_end.
It will make leaves and then the leaves will "die" when the tree grows taller.

now, if evaluate_affectMaterial() gets an affMat that has a satNeeded = M_no_saturation it will work.
previously, this did not work properly.
^ tree. ^ evaluation of grid and affectMaterials. more bugs/errors being sorted out.

The tree synthesis is coming along nicely.

I also added a picture demonstrating JP's horizontal line tool as a caligraphy brush.
That worked out better that I had hoped.

added nighly build for tonight! May 27th night (May 28th early morning)
Merge branch 'tree' of https://github.com/jensenr30/GridSim into tree

Conflicts:
	cell_engine.h
	materials_and_cells.h