Fix for MultiArgument methods (allows single arguments for methods)

MethodSetter --> added boolean to constructor for isMultiValued, edited 'isMultiValues()' method to return this
Setters --> always sets isMultiValued to true, not sure if this is valid for all cases (unsure of use cases for Setters)
ClassParser --> added handling for isMultiValued, Options always set to true, arguments check via Argument object
Setters --> updated to take into account of 'multiValued' for arguments when creating a setter