Add support for g-keys combinations

[Ginden]

Related to #32 and #15

[Ginden]

@JSubelj Hey, any news on this PR?

[suabo]

Hi and thank you for your pull request.
I looked through it and thought a little bit about it. To make this feature work you need one gkey macro set to nothing or something not interrupting if you use a combination. I just thought of normal shortcuts. They always use keys that don't do anything if press on their own like strg, shift or maybe alt. The problem i see is that if you configured all your gkeys it is most likely you will not only run the command on the combination. If you don't manage to press the keys at the very same time the key you press first will also fire and run the configured macro. A much better way to add more macros would be to add support for strg+g[1-9] and shift+g[1-9]. I would also prefer to take the right strg and shift keys for combinations.

I would like to hear another opinion on this topic.

Since I merged a lot of other pull request there is also a lot of conflicts.