InvalidCastException when expression contains power with double exponent (x ^ 0,2)

[bcgrillo]

Where I try evaluate a expression like "2 ^0,2", the program throws a InvalidCastException

System.InvalidCastException: Unable to cast object of type 'Flee.ExpressionElements.Literals.Real.DoubleLiteralElement' to type 'Flee.ExpressionElements.Literals.Integral.Int32LiteralElement'. at Flee.ExpressionElements.ArithmeticElement.get_IsOptimizablePower()

I could solve this changing the method "IsOptimizablePower" like this: https://github.com/mparlak/Flee/pull/31/commits/348cb5157c9ec75da13eb1212caaea20f5df0bc4