Removed explicit insertion of null character into query string when building return value for Query::preview() and Query::preview_char(). Because the library is now aware of null characters in query strings, this causes code that calls preview*() before executing the query to fail.  The new code should avoid that without breaking code that expects to see null-terminated strings, particularly those that call preview_char(), rather than preview().
Removed explicit insertion of null character into query string when
building return value for Query::preview() and Query::preview_char().
Because the library is now aware of null characters in query strings,
this causes code that calls preview*() before executing the query to
fail.  The new code should avoid that without breaking code that expects
to see null-terminated strings, particularly those that call
preview_char(), rather than preview().

winsock/mysqlpp,winsock/mysqlpp,winsock/mysqlpp