Q: Parental Master Password

No, sorry, there is no such feature. You can only set the restrictions described in the support article from which you came, plus a couple of others (such as disabling the ability to take a screen shot) by using Apple Configurator. There is no way to set an overall master passcode.

Regards.

You do want to  be the first to set Activation lock.  This way you can at least restore you ipad should it get locked out.

Activation lock

Find My iPad

"With iOS 7, Find My iPhone includes a new feature called Activation Lock, which is designed to prevent anyone else from using your iPhone, iPad, or iPod touch if you ever lose it. It starts working the moment you turn on Find My iPhone in iOS 7."

http://support.apple.com/kb/HT5818

How Do I Block Websites on My iPad?

http://www.ehow.com/how_8716944_do-block-websites-ipad.html#ixzz2lh8910jd

How To Set Parental Controls and Block Content on the iPhone, iPad, and iPod touch

http://blog.laptopmag.com/how-to-set-parental-controls-and-block-content-on-the- iphone-ipad-and-ipod-touch

How to block specific websites from being accessed with Safari for iPhone and iPad

http://www.imore.com/how-block-specific-websites-being-accessed-safari-iphone-an d-ipad

How To Setup Parental Controls On The iPad

http://content.mobicip.com/content/how-setup-parental-controls-ipad

ParentKit.

https://itunes.apple.com/us/app/parentkit/id600618138?ls=1&mt=8

Parental TimeLock - Time limit for children

https://itunes.apple.com/us/app/parental-timelock-time-limit/id689577280?ls=1&am p;mt

 Cheers, Tom