fixed minor error in comments for OpticalPSF
fixed error in interpolant query in OpticalPSF, also fixed a couple of whitespaces that I spotted so as to match the style guide
improved handling of interpolants for OpticalPSF and AtmosphericPSF objects as suggested by Mike on #329
removed obsolete comments about scipy dependency in lensing engine
fixed second example for getShear() in lensing.py
made first version of TabulatedPk class which basically works
(#305)
allow user to specify interpolant
(#305)
clarify what inputs are allowed
(#305)
clarify what inputs are allowed for table as well
(#305)
Merge branch 'master' into #305