Refactor rbindkeys, with the help of rebocop. (/spec leave untouched)

[zw963]

Almost no change any things, test is passed.

Just code optimize, and fix many typo.

more ruby style. ; )

[zw963]

Thank you very much for this wonderful gem.

[zw963]

Hi, here I create a new project: (with another name)

https://github.com/zw963/linux_key_rebinding

What I used is all from your's gem, I think I should let you know.

I change some code, I hope can merge to rbindkeys someday.

and I hope uys which does not use ruby can benefit from this project.

Thanks.