Fix inproper type value on getLongAt.

Hi,

I found one bug in getLongAt function.
Ti.Codec.decodeNumer is called with Ti.Codec.TYPE_LONG.
but it should be TYPE_INT since TYPE_LONG is for 64 bit integer.
Would you please check it?

This could be a reason why 0th IFD offset doesn't return 0x00000008 ?

Regards,