Fixed incorrect read_uint16 and added new readers to packet base.
Fixed incorrect read_uint16 and added new readers to packet base.

The read_uint16 method was unpacking as a signed integer rather than
unsigned.

A read_int16 method has been added. It unpacks data as signed 16-bit
integers.

A read_sbyte method has been added. It unpacks data as signed bytes.

fallenoak/wow-data