What this allows us to do is much better relationship tracking between
sessions and invoices. The CASS file already has all the structure we
need, and it would be silly to replicate it via complicated time
association algorithms. This approach uses the linear nature of the
data file to track the position relative to other entries.
The timeline module is then responsible for making changes to the
internal representation (in case it is being used as a library for
multi-query commands), and emitting a `Delta` type that can be used to
easily patch the IR in question, because the mapping between the
timeline and IR representations is linear.
This commit does kind of a lot to get cass(1) over the finish line.
For one it implements all the CLI functions (well, almost all) with
their respective parameters, and also creates a new `gen` module which
uses the IR stream to generate a new file based on the old one, while
updating header fields that need to be updated (currently only
`version`).
This version does nothing with the actual header values, and probably
has a lot of bugs. More documentation will follow in future
cassiopeia commits.
Katharina Fey