* remove text alignment, per-box hover for grid, fix mergeValues
* unconditionally set spanNulls = -1
* fix stroke width offset math
* split multi-hover, so only single mark overlays in grid mode
* restore alignValue in state-timeline
* better descriptions, maybe
* init field.config.custom if necessary
* don't show last out-of-view value
Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
