new rez position for mesh post; renamed

Carina Asbrink created a 1 prim LI mesh variation based on my ball&chain
design. I renamed it to "OpenCollar Post" as some people were confused
why a sphere thing popped up if they clicked Rez Post. There have not
been any changes in Toy Wylie's grabbypost script; the folder has been
renamed to reflect the new name of the in-world object.