Fix for issue 7.  (Will not compile due to missing cstring and cstrings)

Hi Herzi.  Please pull this into the db2.js repo.  The changes are very minor and safe.  I looked at the include files.  They have #ifndef inside them, therefore there is no reason to conditionally include in the connection.cc.

I hope to make more contributions like allow CHAR fields so we do not have to CAST our SQL.  BTW, this is working with DB2 on zOS.  Cool!  Thank you for making this.