Merge pull request #83 from mrshirts/nk

Extensive conversion from u_kln->u_kn formalism.  Still need to debug `import version` issues with travis-ci.
Change numpy to np in mbar.py
Merge pull request #92 from kyleabeauchamp/nk

Change numpy to np in mbar.py
Fixed some import errors and moved harmonic_oscillators_update.py to a better location
Merge pull request #97 from choderalab/nkfix

Fixed some import errors and moved harmonic_oscillators_update.py
Fix version issue
Merge pull request #99 from rmcgibbo/fix-version-issue

Fix version issue
Merge remote-tracking branch 'upstream/nk' into nk

Conflicts:
	pymbar/mbar.py