Handle/send version date as Unix epoch, include fallback
Since pull request #392 for Quassel is merged, Quasseldroid should send the client version date as seconds from Unix epoch in QString
format, and should also try to parse incoming version dates as seconds from epoch, and if it fails, revert to previous behavior of showing it as a string.
This change allows Quassel clients to display a localized version date. Legacy Quassel clients will just show a Unix epoch, not a big issue.
If Quasseldroid does not already, it should also fill in Unknown date
or such whenever the version date is empty. Quassel desktop will begin doing this whenever the above-linked pull request is merged.
See upstream pull request #392 for Quassel for more details and rationale.
Upstream pull request is merged.