* Allow HMX components in markdown
This adds support for HMX components in markdown. The mechanism for importing is via frontmatter. We could do this differently (setup script maybe?) but since this was the easiest to implement I thought it was a good first-pass option.
* Remove node-fetch from snowpack config
* Assert that the runtime is created successfully
* Add back in the micromark extension for encoding entities
* Encode both codeTextData and codeFlowValue
* Install snowpack app's deps
* Add support for React components.
This adds support for react components via a new `extensions` config in astro.config.mjs. In the future we can extend this to do things like look at the import statements, as Snowpack does.
* Fix the tests
* Initial tests set up
This adds tests using uvu (we can switch if people want) and restructures things a bit so that it's easier to test.
Like in snowpack you set up a little project. In our tests you can say:
```js
const result = await runtime.load('/blog/hello-world')
```
And analyze the result. I included a `test-helpers.js` which has a function that will turn HTML into a cheerio instance, for inspecting the result HTML.
* Bring snowpack example in
* Formatting
