v0.4.0

This is a full rewrite of the core algorithm. We now construct the entities into a tree, and then serialise recursively. The simple case remains unchanged:

toHTML(ctx.message); //-> html string
toMarkdownV2(ctx.message); //-> Markdown string

There are some changes to the advanced API:

• serialiseWith now takes two arguments, serialiser and escaper.
• Serialiser and Escaper types are exported, for more convenience if you want to implement your own.
• Serialiser now takes (match: string, node: Node); see types for more details.