Switch to BASE 3.20

[Nicklas Nordborg]

The new feature of with subcontexts in list pages can be used to restrict when the variant search columns are visible.

[Nicklas Nordborg]

In 7894:

References #1619: Switch to BASE 3.20

Updated JAR references.

[Nicklas Nordborg]

In 7895:

References #1619: Switch to BASE 3.20

Only display varsearch version on the varsearch pages.

[Nicklas Nordborg]

In 7896:

References #1619: Switch to BASE 3.20

Decide if a column should be hidden or not depending on subtype in the current context.

[Nicklas Nordborg]

In 7911:

References #1619: Switch to BASE 3.20

Compile against same Slf4j version as used by BASE 3.20.