X axis belt tensioner with bearings for the Da Vinci 3D printer

A remix of the belt tensioner [thing:690090](http://www.thingiverse.com/thing:690090) that uses 2 x MR63ZZ (3x6x2.5mm) ball bearings mounted on the stock pulley.

It makes for a more durable setup that prevents known issues with the stock tensioner, such as squeaking noises and non round circles, that typically develop after a number of printing hours.

With this design it's also significantly easier to insert and remove the pulley, while still keeping the exact same tension as the stock