Button that links remotes

[eliaspinero]

This PR addresses issue #1

Did this PR on the right repo this time

[mvahowe]

I don't think the button works. I created a local project LMTT, pushed it and pulled it, resulting in this:

$ ls pankosmia_repos/git.door43.org/BurritoTruck/
en_bsb  en_fiaimages  en_sq  fr_lsga  fr_vp  LMTT  MT  my_bcl
$ ls pankosmia_repos/_local_/_local_
LMTT  MT

but the "connect" button remains disabled.

Also:

• there are a lot of unused imports and variables
• please remove commented code. This time it caused a merge conflict that took three commits to fix
• the appbar should be "secondary" - see other dialogs that Loïse has tidied up.

[mvahowe]

@eliaspinero I think this is one place where we got stuck because the git pull operation was throwing an error with Windows (even though it seems like the actual pull happens). The latest desktop-app-pithekos can compile a debug version of the server. (You need to add -d to build_server and then to run. I'm hoping we'll see more output in the server console. (It may be one or a few words, I put in about 50 different messages for each point where things might fail.)