#89 Man page symbology list omits "qr"

[Richard Neill]

The man page contains
----
-S[symbology.]config[=value], --set [symbology.]config[=value]
           Set decoder configuration option config for symbology to value.  value defaults to 1 if omitted.  symbology is one of ean13, ean8, upca, upce, isbn13, isbn10, i25, code39, code128
           or the special value *.
------

This doesn't include the "qr" type in the list. I think it should be there.

(I have verified that, for example, "-S *.disable -S qr.enable" does what I expect).

It would also be helpful to know... is there any significant performance boost to be had by doing this?