i3-client can become nil (fix included)

[ThibautVerron]

Hi,

Thanks for your package!

I have run into some minor issues when i3-client is nil. I don't know what causes it, but replacing (boundp 'i3-client) with (bound-and-true-p i3-client) in the test of i3-get-or-make-client (i.e, treating a nil value in the same way as an unassigned value and spawning a proces in this case) seems to work around the issue.

It would also allow to write the whole function as

(or (bound-and-true-p i3-client)
    (setq i3-client
          (<code to spawn the new client>)))

[vava]

Thanks for feedback! I'll try to find time to make changes but please feel free to send a pull request and I'll happily merge it in.