Midis without tempo data plays with tempo of previous midi

[Yoshi1229]

Just a minor bug
This bug was fixed back in 2.0.1, but in recent versions this seems to be happening again
#13
Take the midis back in issue 13 as example, loading 147.mid for the first time plays it at 120bpm. However, after playing 77.mid then playing 147.mid again, it seems to be playing at 230bpm.
Is this due to a recent fix on another issue? Seems that the defaultTempo variable is changed in the dry run