This removes text wrapping from col-spanned headers inside a classtable...needed for half-tables that contain `--- Spells Slots per Spell Level ---` so they don't wrap to next line.
Both v3 and Legacy
Add a `.frame` class for Class Tables so that the frame and background can be toggled on or off in a similar fashion to the new monster stat block.
This will allow a class table to be used as a "third caster archetype" table such as referenced in PR #1079. Adds consistency with Monster blocks, too.
- add "- spell slots per spell level -" header to full class tables
- add rules for `.classTables.full` which is similar to `wide` but adds the previously mentioned header as well.
- add css variable `--row-color` so the odd row colors can be set in the inline moustache syntax easily.
