Fixed SCAD and Updated

Scad source was missing the line PC_H = 13;

Added rendering options and removed static $fn assignments.

Added ability to use a parameter to select rendering pin/plug/both.

Minor cleanup of differences for preview view.

README.txt

@@ -1 +1,10 @@
-Lian Li PC-60A front-side connectors by srepmub on Thingiverse: https://www.thingiverse.com/thing:215612
+Lian Li PC-60A front-side connectors
+
+Original by srepmub on Thingiverse: https://www.thingiverse.com/thing:215612
+
+These are tested working replicas of the clips used by LianLi to hold the
+front panel on a PC-60 case; they were also used on other cases including the
+PC-9F.
+
+Plug will mate snugly with original pins.
+