Unity's "show the launcher" key is not really customizable

I've been using "<Super>..." key bindings for window/workspace navigation for many years in plain compiz and I would like to continue to use them in Unity. Unfortunately right now (4.20.0) "<Super>" is somewhat monopolized by Unity (the key bindings I want to use are ignored). I tried to change (via ccsm) launcher key binding from "<Super>" to "<Super>Return" and got weird behavior. Most of the times the dash doesn't show up, unless you hit Enter two times very fast. I've looked into the source code and found that there is complex tapping logic involved and additional hardcoded "<Super>KP_*" key bindings are registered, so it is no surprise that my two-key combination doesn't work. I wrote and attached a patch that adds a key binding (in "Experimental" tab) for just showing the dash, hopefully it will be useful to other people with similar keyboard habits. Please consider merging it.