lego brick compatible tracks

Remix of https://www.thingiverse.com/thing:3991801

I decided to print my own tracks (1.25 x 4.4 x 128) instead of sourcing brass sections -- works really well!

I reworked completely the "track holder" (rail_support.scad) starting from the great https://www.thingiverse.com/thing:615256 to have a lego-like part as a base.

Profile based on http://l-gauge.org/wiki/index.php?title=Track_Geometry