RFE#1145: Preview SQL instead of executing it.

RFE#1145: Preview SQL instead of executing it.
https://sourceforge.net/p/phpmyadmin/feature-requests/1145/

![rfe_1145](https://cloud.githubusercontent.com/assets/6863616/3204330/4c3508ce-eda7-11e3-8a71-67fc4c554f01.png)


Signed-off-by: Ashutosh Dhundhara <ashutoshdhundhara@yahoo.com>