Z-axis optical endstop (Re-D-Bot)

Hello there! (=
So, this is a new [OptoEndstop](http://reprap.org/wiki/OptoEndstop_2.1) mount, for Re-D-Bot, D-Bot and D-Bot analogs.

**Endstops** I used: http://ali.pub/7z31t

P'S: I love this, very easy to adjust after nozzle change, if it required. And as result nice first layer, I'm pretty glad. ~_~

**03 February. Update:** 02_Cap.STL size was fixed (; Thank you for response