Hide password from login screen

[nsg]

The password field is plain visible text, not a problem if I'm all alone but that's not always the case :)

[Henningstone]

Is that even possible without modifying nanogui? I looked through it a bit but didn't find any possibility to create actual password fields...

[nsg]

I'm afraid that's the case. Maybe it's not to hard to patch that in, and maybe the upstream developer will merge the change so we do not need to maintain a fork. What do you think? @petterarvidsson