usbuart-case: fix bottom half which would get in the way of SW1 pins

usbuart-case/usbuart-case.scad

@@ -55,7 +55,7 @@ j456_xoff = 11.926;
 j456_yoff = j7_yoff - 1.236 - j456_length;
 
 // pcb
-%linear_extrude(pcb_thickness) square([pcb_width, pcb_length]);
+//%linear_extrude(pcb_thickness) square([pcb_width, pcb_length]);
 
 // case etc
 translate([0,0,0],$fn=40) difference() {
@@ -208,6 +208,7 @@ translate([0,0,-groove_thickness],$fn=40) difference() {
            square([pcb_width, pcb_length]);
            translate([groove_width,groove_width])
                square([pcb_width-groove_width*2,pcb_length-groove_width*2]);
+           translate([pcb_width-4,sw1_yoff]) square([8, sw1_width]);
        }
         
        // hole 1 bearing