Enhancement: disable screen lock

[magdesign]

Would be lovely to have an option in settings to disable screenlock (as we have on organicmaps).

When phone screen goes to sleep and we reactivate it, osmin should be present without unlocking screen code

[janbar]

"Preventing screen lock" is already implemented in osmin. It is enabled automatically when you are in navigation mode. In view mode, screen locking is enabled to save your battery.

[janbar]

The commits for the issue #60 should resolve this on freedesktop platform. So for instance the "Preventing screen lock" is implemented for Android and freedesktop platforms.
Have to know that each platform requires its own implementation unfortunately.