fix negative base 10 number support in IntToUCS2, and return 'NaN' for ToString(NaN)
fix negative base 10 number support in IntToUCS2, and return 'NaN' for ToString(NaN)

carlosalberto/echo-js,carlosalberto/echo-js,toshok/echojs,toshok/echojs,toshok/echojs,carlosalberto/echo-js,toshok/echojs,carlosalberto/echo-js,toshok/echojs,toshok/echojs,carlosalberto/echo-js,toshok/echojs,carlosalberto/echo-js,toshok/echojs