Unpack some small fields

[sjakobi]

In an earlier iteration I had also UNPACKed some Text fields. But then I noticed that we don't actually look at them so often, so I assumed it's not worth it.

Context: #121

[sjakobi]

I wonder whether this is a breaking change with regards to the PVP?

If any entity was removed, or the types of any entities or the definitions of datatypes or classes were changed, or orphan instances were added or any instances were removed, then the new A.B MUST be greater than the previous A.B.

Do these changes constitute proper changes to "the definitions of datatypes"?

The derived Generic instances change which I guess is sufficient grounds for a major bump…

[quchen]

Strictly speaking, this is a major bump. On the plus side, many changes in prettyprinter warrant major bumps, so this can be packed with another major change, no need for its own release.