Have source location positions change smoothly rather than by jumping

[konstantint]

I.e. let us say the old sources are at positions {p_1, p_2, p_3}. The new sources are located at {q_1, q_2, q_3}.

1. Match up p_i with q_i-s.
2. Set the relevant destination for each source.
3. At each animation frame move each source closer towards its current destination until it reaches it.