Update utils.py

Add all possible interconversions between cm-1,eV,hartree,kcal,kJmol-1 using NIST 2010 CODATA factors and constants
Comprehensive energy interconversions added
Merge pull request #62 from arsphenamine/master

Energy conversions in GAMESS
Add comments about sources
Order and update attributes list in ccData docstring
(cherry picked from commit 0611e0e7fe432680eca66f775b839d0defd61ccd)
ccData: Generate _attrlist from _attrtypes
(cherry picked from commit cf927e6e963d5805c07b096901e6fa1cb679c5a7)
LogFile: set attributes using ccData.setattributes
(cherry picked from commit 3c1032c121c40daf7bbd6c9e2e501832ab475d73)
ccData: check attribute types upon setting (resolves #63)
(cherry picked from commit 7053d776b8e7fb6718c4897ac2b36327fe1f0a2e)