Proof of concept for gradients.

Hoping to use this technique for cloud cover.
Gradient only for this specific one.
shuffle
Temporary fix for epoch x offset.
Merge branch 'fix_epoch' into gradient
Shuffle.
Cloudcover gradient area almost working.
Another step toward cloud cover
Shuffled. Not quite working yet.
No more red stroke around cloud cover.
Showing girder 22 instead.
Ability to hide y axis labels.
Fixed multiChart

Fixes #153