Video projector support

Simple holder for (small) video projector.

Need two external parts :
* http://fr.aliexpress.com/item/Camera-Accessories-Black-Metal-Mini-Ball-Head-for-1-4-Screw-Mount-Tripod-Dolly-DSLR-DC/32664749730.html
* https://www.aliexpress.com/item/1-4-D-Ring-Convert-Slotted-Screw-Pull-Ring-Adapter-For-Camera-Tripod-Monopod-Quick-Release/32401103814.html or https://fr.aliexpress.com/item/Camera-1-4-D-Ring-Convert-Slotted-Screw-Pull-Ring-Adapter-For-Tripod-Monopod-Quick-Release/32657567326.html