Tool Holder for MPCNC 2.8W laser w/ fan and line lasers

No cover so there's potentially some additional ambient cooling benefit (it also looks cool with the danger sticker visible). At very least without the cover it's less to print.

Added a duct to better direct the air flow over and around the heat sink. The line lasers are aligned perpendicular to the work surface to avoid spraying even low power laser radiation around unnecessarily.

##Printing
Rotate 180 degrees and it'll print just fine without supports. In PLA at 0.2mm layer, 100%