fix potential evaluation for general case of TwoPowerSphericalPotential, Integer doesn't work now
fix potential evaluation for general case of TwoPowerSphericalPotential, Integer doesn't work now

followthesheep/galpy,followthesheep/galpy,jobovy/galpy,jobovy/galpy,followthesheep/galpy,jobovy/galpy,followthesheep/galpy,jobovy/galpy