removed unused classes in dualaverage: GrowingBatches, StochasticGradient
removed unused classes in dualaverage: GrowingBatches, StochasticGradient

stan-dev/stan,stan-dev/stan,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/stan