Correctly handle units in parallel event loader

Avoid repeated opening/clsoing of data sets.

Integrate parallel event loader

FakeParserDataGenerator should probably be set up in the reverse way so
reference data is generated based on input data, otherwise conversion of
TOF from and to integer types causes issues.

Do not default to WORLD anymore. This is needed for unit testing on the
algorithm level.

This should be more reliable since it does not require specific naming
conventions. However, there does not seem to be a way to ensure that
banks are contiguous based on information available in the Nexus files.

Binary was 6.5 MB, now 2.8 MB. Is std::future and std::async producing a
lot of code?

And fewer functions with many template arguments.

I think that's what it did.