v0.6.0

• Renamed inserted-spans drawing mode to mark-elements, and switched to using HTML <mark> elements in that mode. <mark> elements are more semantic than <span>, and provide better accessibility for screen readers.
• Added support for editing highlights in the mark-elements drawing mode.
• Added css-active and svg-active options to customize the appearance of active highlights.
• Improved the default style for active underline highlights.
• Improved appearance of overlapping highlights in the mark-elements drawing mode.
• Improved logic to only redraw a modified highlight once, after the user has finished editing.
• Improved logic for detecting changes to the width of the annotatable container, to avoid redrawing SVG highlights unnecessarily.
• Fixed a few cases where selection handles didn't show after creating or editing a highlight in Android Chrome.
• Fixed an issue where a hidden input field (used for initializing selection) was visible to screen readers.
• Fixed an issue where selection handles didn't redraw in the correct location after resizing the window.
• Fixed an issue that could prevent SVG highlights from showing in Android Chrome.
• Fixed an issue where a highlight's rangeHtml string included surrounding links and highlights.
• Fixed an issue where selected text sometimes turned black in dark mode, making it difficult to read.

Full Changelog: 0.5.1...0.6.0