Added a constructor function for PCBs.

PCB text can now specify a colour.
Added SOT23_6, TSOT23_8 and CAP1210 SMD packages.
Added ESP-201 Wifi Module PCB.
Added ESP12F Wifi module.
Added tiny_buck converter PCB.
Made 2p54joiner a bit longer.
Fixed SOIC gullwing shape.
Added Wifi antennas.
Added Yunpen filtered IEC mains inlet.
Added power jack socket.
Added right angle option for LEDs.
Added gear_motors.
Added 686ZZ and 696ZZ ball bearings.
Added two larger box section tubes.
Added right angle option to square_buttons. Doesn't draw the frame yet.
Added multiwatt11 package for L6203.
Added ONS9143A 13A mains socket.
Added radial electrolytic capacitors.
Added LDE10_20B PSU module.
Added screw_tearsink() to make horizontal countersunk holes.
Can now have solid tracks on veroboard.
Added veroboard_base() module to make an STL for a base with spacers.
Corrected M6 spring washer thickness.
Can now specify the height of a solder meniscus.
slot() now has a center option.
Added button_6mm_7 with a taller button.
Added default fa, fs and fn constants used for drawing vitamins.
These can be set via $default_fa and $default_fs that can also be set
by environment variables: NOPSCADLIB_DEFAULT_FA and NOPSCADLIB_DEFAULT_FS.

tests/wire.scad

@@ -109,7 +109,7 @@ module wires() {
 
             ends = [for(p = positions) [[30, p.x, p.y], [0, p.x, p.y]]];
             paths = [for(i = [0 : len(tpaths) - 1]) bezier_join(ends[i], tpaths[i], 1.3, 3)];
-            cable(cable, paths, $fn = 32);
+            cable(cable, paths, $fs = fs, $fa = fa);
         }
 }