* Add headingTypeface to SpannableTheme, use a custom heading typeface in the sample app
* Add headingTextSizes
* Switching to headingTextSizeMultipliers, adding validating annotations, adding example
* Consolidate logic, add crash if header index is out of bounds
* Change LinkSpan to extend URLSpan. Allow default linkColor (if not set explicitly)
* Fit an image without dimensions to canvas width (and keep ratio)
* Add support for separate color for code blocks (#37)
* Added retention annotation for Alignment IntDef (#3)
* Task lists (#4)
* Added since annotation to newly added method/classes
* Fixed the indexes bug for margin spans (#6)
* Feature: Revert spans order (#11)
* SpannableBuilder
* Removed nullablity from Markwon class (no null markdown)
* Image sizes via HTML (#13)
