Add log replay mechanism

[rladstaetter]

Create a functionality to replay log files.

Initially, this should happen solely for development purposes, maybe in a later stage be incorporated in the user interface.

To start with, an simple implementation reads a given log file line by line and writes it again in a new file, every line with a constant delay. This can be useful for testing.

After having implemented parsing of timestamps log files can be replayed. To make things more interesting, log files can be replayed in a 'fast forward' way. This allows to inspect runtime behavior (for example, bursts of activity will be quite apparent then, phases of inactivity as well).