Fixed sql.SQLStr.

### The current sql.SQLStr does not follow the SQL(ite) standard.

### Please see:
https://sqlite.org/lang_keywords.html
(or shorter:) https://www.sqlite.org/faq.html#q14

### Proof of concept:
http://codepad.org/CMl86ET3

### \0
I added a '\0' fix as well, as this is somewhat related.
If you don't want to include it, it's fine, tell me or remove lines 15-18 yourself.

### Information:
On our servers, we have been using this fix for all of our queries since December 2012,
and there have been no problems whatsoever.