Cautious incremental improvements to amberio modules. This rather completely
re-tools the umbrella sampling exchange routines and, in basic tests, appears
to be an order of magnitude faster in delivering the same answer. Still needs
a bit more testing but I'm developing while traveling...

Also trying to benefit from recent additions to the Python modules in the
upcoming release of AMBER14. This whole package may eventually just disappear
into the (freely licensed) parts of AmberTools.
Merge branch 'master' of https://github.com/saga-project/asyncre-bigjob