Edited English strings in Dev version of ThemeKey 6.x-3

Patch attached... hope I've done this right. :-)

Another small patch to add to that one -- it is not cumulative, but it does include a few things that were already in the first patch (I took the project home and submitted the final original patch from a copy at home -- the copy I have here has a few early edits, plus the intended one, but is missing most other edits.)

This patch is intended just to remove a short paragraph (in themekey_help.inc) mentioning and linking to Themekey Properties as a separate module -- of course it's now integrated into Themekey in the D7 port.

Okay... hmmm... I think I must have meant to attach this patch to the D7 version, not D6, since it's about removing the reference to Themekey Properties. Anyway, I'll make a new patch.