make target refs in lms weak break cylindricalrefs
Transformable has to have copy now
from_vector attempts to .copy(), warn if not poss
compose attempts to .copy(), warn if deepcopy
OrthoPDM attempts copy of model, warn if deepcopy
remove eepcopy from fitting result
fix MockFittingResult
Merge pull request #394 from jabooth/memfixes

weakref to break cyclic references