General improvements for the Baserock Import tool
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Currently the tool hardcodes the name of each chunk morphology it generates as
'strata/$stratumname/$chunkname-$version.morph'. This is more or less a
workaround for some of the issues listed below.

It's ugly to have the version number in every chunk name, and it makes it more
time-consuming to do version updates of individual components in a stratum.
The chunk name should default to '$chunkname', except when multiple versions
of the chunk are found.