Basically, if the paste position is not zero and not on a bar line, we will a BBT marker there,
using the existing tempo & meter at that position before the paste.
If the end of the paste is not on a bar line, we will place a BBT marker there,
using the tempo & meter that existed before the paste.
TempoMap::paste() now also accepts an optional final argument that if provided is
used to name the BBT markers, if they are created
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