MakeBlock Parametric L Bracket

This is a work-in-progress; I'm still refining the holes and the offset near the bend.

This is a parametric L-shaped bracket generator for MakeBlock which can generate parts of various sizes, similar to my [MakeBlock Parametric Straight Bracket](http://www.thingiverse.com/thing:1133920). All MakeBlock structural parts use M4 screws with the holes separated by an 8mm pitch, so I created this generator to generate L-shaped parts with a specified number of holes in the x, y, and z directions (as well as the part thickness). Most printers close inner holes up a bit, so a 2mm radius will create a part where the M4 screws "bite", and 2.4mm radius will create one where they're loose and need a nut. You can change all parameters in Customizer (be sure to scroll down to see them all) or by downloading the .scad file and opening it in OpenSCAD.

The part prints on its side. By default the holes are in the shape of small octagons to allow most extrusion printers to print them accurately,