VC has issues with default argument

so split the function in two
bump RMF
remove broken link

close #727
remove broken link

close #726
fix poorly named variable

close #716
pull large function out of header

close #714
provide function to walk up rigid body tree

relates #704
it is not always legal to inspect derivatives

as they are not always defined.
add test for container update

close #730.

Also fix problem with rigid bodies and close pairs. Probably relates salilab/pmi#19
clean up container tests a bit
mark benchmarks as benchmarks
bump rmf