Handle more expressionIsInferred toggling on Durations

[jacobtylerwalls]

#908 didn't handle toggling .expressionIsInferred back to False when setting type/dots after construction.

No change when setting tuplets, since part of the point is that for numeric durations such as 4/3, they still bear .expressionIsInferred = True even when expressed with tuplets.

While here, I noticed that the attribute should likely be set True when setting numeric qL on unlinked durations, not just on linked durations.

[coveralls]

Coverage increased (+0.01%) to 92.355% when pulling 9434d13 on jacobtylerwalls:set-duration-type into 0d373bd on cuthbertLab:master.

[mscuthbert]

This is great for me!