Enaml-web

- **BREAKING** remove the `before` key from `added` and moved modified `events`.
The index can be used instead.
- Add oldvalue to update events
- Speedup looking up the index when adding child nodes
- Fix block insertion into another block that has a `block` set
- Cleanup some uncecesesary code
- Use etree.tostring instead of html.tostring to speed up render
- Add destroy methods
- Drop usage of atomref

- Include new index in added and moved modification events
- Fix bug where pattern nodes caused nodes to be inserted in the incorrect order

- Fix error when `Raw` node source is empty string.
- Make ext optional

- Allow `Raw` node to accept an etree element for the it's source.

- Move to python 3 only syntax and add typing annotations
- Reformat with black
- Add `dragstart` and `dragover` events to `Tag`
- Slightly speed up init_widget and use lru cache for determining attributes
- Use lru cache for proxy resolve class
- Remove unused init functions
- Remove logger and database from WebApplication, if you want those add them
in a subclass.
- Change id generator to use a shorter (but slightly slower) version

Make markdown source modified event return the rendered value

> This is the last version that works on python 2.7