Vector tag parsing into TQTaggable

Release notes

Single tags in configs were parsed wrongly in a very specific (and presumably rare) case. More details in MR.

Details

A small bug that caused configs of the form

a.b.0: value
a: otherValue

to be parsed wrongly. They were parsed correctly in case the oder was swapped. To see if a vector tag already exists when adding a, all tags starting with a. and ending with an integer were considered. Now, all tags starting with a. and followed by an integer are considered. Note that in most relevant cases (a.0, a), the treatment is the same.

Closes #299 (closed)