Settings menu

[kirillt]

The app needs new screen for various tweaks, all settings from that menu must be persisted.

[kirillt]

Desired options in the settings screen:

• crash reporting over internet
• images cache replication
• images thumbnails generation
• reset all preferences

[kirillt]

This issue might be referenced by other issues needing a preference. But menu itself is implemented, so I'm closing it.