connect.reload needs a stream of files to fire, but this stream is irrelevant here and slows refresh time a lot (from ~2ms to 2000ms here)

allows custom themes to import files from subfolders inside the `css/theme/source` folder.

in `css/theme/source/custom-theme.scss` we can now do
```scss
@import `custom-theme/controls`
@import `custom-theme/headings`
...
```

may allow perf boost

Currently it's only watching for changes to `.html` and `.md` files located in the root of the project. I was frustrated when livereload stopped working for me: turns out it was because I put my content into subfolders.

refactor hash parsing, fixes issue with autoplaying media not starting from internal links on mobile devices