Addressed a RangedNumberGenerator issue in scenarios where multiple heterogeneous requests contain System.Int16 operands; the first request is for System.Int16, another request is for an operand with maximum value greater than System.Int16.MaxValue and then, the next request contains a System.Int16 operand - at that time the state is greater than System.Int16.MaxValue (where a System.OverflowException was thrown, as reported in #295).
Returned a 16-bit signed integer (instead of returning a 32-bit signed integer) when adding two 16-bit signed integer numbers.