Improve stopping and wiping behavior

• Progress indicator for stopping
• Progress indicator for wiping
• More logging during startup and stopping for debugging
• Put post wiping fragment into separate process
• Improve exiting behavior on stop/wipe
• Make wiping fragment display transition to stopping once wiping is done (by changing the status text view)
• Make stopping and wiping take at least 1 second so that the user can perceive what's going on if these finish very quickly on fast devices
• When detecting on startup, that the app is already stopping or wiping, display the stoppin/wiping fragment instead of failing silently
• Exit application when reaching STOPPED state, independent of lifecycle

Closes #60 (closed)