Fix warnings in overload_numeric.i.
./../overload_numeric.i:36: Warning 509: Overloaded method Nums::over(short) effectively ignored,
./../overload_numeric.i:33: Warning 509: as it is shadowed by Nums::over(signed char).
./../overload_numeric.i:39: Warning 509: Overloaded method Nums::over(int) effectively ignored,
./../overload_numeric.i:33: Warning 509: as it is shadowed by Nums::over(signed char).
Add overload_numeric_runme.ml.
