Output time for stress autocorrelation.
Small error in PairPotentialImpl fixed.
Adding a general ordering external potential.
Changes to ddMd diagnostics
Revert "Changes to ddMd diagnostics"

This reverts commit b28edd8c8e9264fa6809c742c3126b2e43a36bdf.
Merge branch 'master' of git://github.com/dmorse/simpatico
Merge branch 'master' of github.com:medapuram/simpatico

Conflicts:
	src/mcMd/diagnostics/mcSystem/McStressAutoCorr.cpp
Merge branch 'master' of git://github.com/dmorse/simpatico
Merge branch 'master' of git://github.com/dmorse/simpatico
Changes in external potential class.
Merge branch 'master' of git://github.com/dmorse/simpatico
Name change TanhCosineExternal -> LamellarOrderingExternal
Changes in hoomd module to update it with the remaining changes in simpatico
Merge pull request #14 from medapuram/master

Changes to inter/external.
Documentation, mostly for external interactions.
Merge branch 'master' of github.com:/dmorse/simpatico