Issue 86 clear panel

[karlgrz]

Implemented a "Autoclear panel" checkbox and corresponding duration control in the Config tab.

Then, when the duration has passed, the content panel is cleared, like so:

I also updated .gitignore for the artifacts generated from building on ubuntu (I was just running qmake && make in the qtpass root and then running the binary generated like ./qtpass if there's a better, cleaner way let me know.

[annejan]

Wow, thanks, that's fast :)

Will give it a quick one-over and add Dutch and German translations for it

I was never really bothererd by the artifacts (on OSX or Arch), but it's also a good addition to the .gitignore

I don't think there is really a cleaner way to do things.

[annejan]

Looks great on first viewing and reading the diffs (on mobile)

You also made me uncover an inconsistency that slipped in using the autoclear value for the hide on start. Thanks :)

[karlgrz]

Double bonus!