clean up Function spec
clean up FunctionPresenter spec
Decompositions: elaborate spec and wire implementation properly
unwrap Circuit#initialize
clean-up Circuit.from_fsm spec
clean-up Circuit spec
clean-up Circuit#{not_smaller_than,size} specs
rename Circuit{,Sizer}#not_smaller_than to #min_size
factor out Circuit.new spec
clean-up CircuitPresenter spec
clean-up CircuitDecomposer spec