Fixed bug in nuclearAttractionIntegral. Restructured E and R out of
GaussianTypeOrbitalIntegrator.
Comment cleaning.
Pulled all integrals out of GaussianTypeOrbitalIntegrator into
respective classes.
All integrals close to working, but with
GaussianTypeColoumbAttractionIntegral tests failing.
Fixed bug in HermiteExpansionCoefficient that caused
GaussianTypeColoumbAttractionIntegral tests to fail.