That the "parse" method defines a number callback prevents the integer and double callbacks from ever being invoked

[lehenbauer]

From examining the yajl source and docs, if a non-null number callback function is defined in a yajl_callbacks structure and subsequently passed to yajltcl_make_parser, when the parser is used, the integer and double callbacks will never be invoked.

We should be able to change the number_callback in the "yajl_callbacks callbacks" structure definition to NULL and delete the number_callback function and gain a slight performance improvement in the "parse" method.

It's an easy fix but it could stand to be tested.

The parse2json method defines a number callback but does not define integer or double callbacks, so no change is needed there.