Rename `src/` to `dist/`

Use the `dist/` directory to store the distribution files.

Note: Right now, since the `.htaccess` file isn't automatically
generated (which it will at some point), it isn't really that
useful to store it in the `src/` directory.
Make `.editorconfig` better reflect indent usage

Update the `.editorconfig` file to reflect the fact that
the indent size used in the `.travis.yml` file is 2 spaces.
Add note about the `RewriteOptions` directive

Ref: h5bp/server-configs-apache#36.
Close: h5bp/server-configs-apache#37.
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