Upgrade QLI Installer and use Cal's Qt Mirror for more stable Windows builds

[nelsonjchen]

The default Qt Mirror has been having strange connectivity issues and timeouts. This is causing timeouts and brownouts of Windows builds.

As an alternative, perhaps we should try using a mirror of the Qt repository instead of just Qt's. I've added support to use alternate mirrors to my fork of QLI Installer. (I've opened an issue on that nicer fork to add this feature as well)

From a mirror list, I've picked UC Berkeley's mirror as an alternative since I believe it to be the biggest and most stable alternative mirror to the other commercial or enthusiast mirrors in North America. It's almost government.

[AdrianKoshka]

That's odd, the linux build failed. Otherwise, sounds good to me.

Fetched 17.3 MB in 5s (3,270 kB/s)

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
##[error]Bash exited with code '100'.
##[section]Finishing: Install Dependencies

[nelsonjchen]

The Linux build needs an ‘apt update’. I’ll make a separate PR for that.

[nelsonjchen]

Actually, I'll be making a seperate PR for Linux anyway. The dependencies there need to be locked down.

[AdrianKoshka]

Going to assume this PR is safe to pull in now?

[nelsonjchen]

Yeah it's safe. We can always change it more later.

…

On Sun, May 26, 2019 at 10:20 AM Adrian Lucrèce Céleste < ***@***.***> wrote: Going to assume this PR is safe to pull in now? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#318?email_source=notifications&email_token=AAABJ4YBIGLMWLD7AZ7744DPXLBF3A5CNFSM4HPWD7G2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODWIJ4MY#issuecomment-496016947>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAABJ42HTMRTYRGJTLEGQWLPXLBF3ANCNFSM4HPWD7GQ> .