added a test from the experimental branch for checking.
merged generalzations.
included a treshold to the number of crystallized neighbors a site must
have to be  able to crystallize itself.
got an assertion for active surface for crystal lim > 1
note: its for == 1 as well.
assertion for nntc==1. Active surface.
the threshold on particle is implemented. However knowncase now do not
work.
reverted some stuff to make the knowncase test pass.
merged with remote branch