Should panels be sideways expandable or otherwise allow for long formulas?

[katestange]

The addition of colour formulas has really increased the formula complexity that occurs in panels. Should we have multi-line inputs or allow for the parameter panes to be dragged to become wider?

[gwhitney]

One simple option would be to have all formulas be textareas (multiline text input) rather than ordinary text, but that will take up a bunch more space for every formula.

[gwhitney]

This should be done once #542 is merged.