fix: zero len nchar.

fix: zero len nchar.

fix the problem running on x32 bit system

pre-release version 2 of the client major changes:

1- update client version to:
2- update ttc version to: 9
3- use 4 byte packet length instead of 2 bytes
4- use advanced negotiation
5- define NCHARSET in the data type negotiation and
6- use big clear chunks
7- use more verifier type in authentication object
8- receive session properties after authentication without calling getNLSData()

Merge pull request sijms#60 from sijms/dev

Refactored GetNLS not to issue 14 queries, eliminated slow & unnecessary for loop.

some performance fix (replacing appending bytes to bytes.Buffer.Write())