Release 0.2.0

[jrmoulton]

There are a few things left that I'd like to see done before 0.2.0. Hopefully that can happen very soon

• Simplify dropdown, add constructors, add docs #618 Rethink the API for creating elements with the builder pattern (also related document dropdown menu #621)
• dont send pointer events to overlap siblings #648
• Views module docs #620
• Fix view transition example
• Merge this todo app example as an example of a slightly more complex app https://github.com/jrmoulton/floem/tree/add-todo-app-ex
• Update changelog

[jrmoulton]

I had been planning on working more on the documentation before the next release but at this point I think it would just be good to get a release out as soon as possible

[dzhou121]

Thanks for organising this. We've made tons of changes/improvements since 0.1.0