Adds a new AnchoredBox component that is functionally a clone of the "saving error" notifications, but drops a lot of the JS in favor of the new (chrome-only!) CSS Anchor Positioning API. In subsequent commits, either alternate styling or a polyfill will be added non-supported browsers.
The box contains a few inputs that modify the CSS applied to `.pages`, most critically a "start on right" toggle for the Facing Pages mode.
The range slider should only display a tooltip for the value if the value attribute exists. For example, the difference between controlled and uncontrolled inputs.
Update toolBar.less
Adding class name so that it can be toggled between 'recto' and 'verso'. Verso being the normal left/right configuration, no styling is needed. With recto, the first page is shifted to the second slot, or right side.
Adding the margin resets back in because otherwise each .page margin is set to "auto" on the sides, and that makes them zoom awkwardly when in facing and flow modes.
Toggles a state variable to either visible or hidden which is used to set a related class on the toolbar. The hiding is done with CSS, just reducing the width of the toolbar and the opacity of the tools.
All zoom buttons run through same handler now.
They no longer take only the delta of the current zoom and desired zoom-- they take the actual desired zoom.
calculateZoom is now calculateChange, to help get the desired delta.
Removes icons as components, uses mask-image instead.
Sets a size on the .fac icons to 1em so by default they are 1em and retain their aspect ratio.
rename the icon files for consistency.
