Add single-letter aliases for --dev and --port

It would be very handy to be able to write `lume -sd` or `lume -sdp 80`,
for example.

This reverts commit be274c7ecc7877a18dcc2a8158009168a9f99968.

Update rest of dependencies

This also adds the missing version numbers.

Allow adding slug chars again

Allow empty front matter

The Unicode normalization does not cover all,
so it’s still good to have a way to add custom cha...

Fixes #52

Show local IP address on serve

Using the address, you can test the site,
for example, on your phone in the same network.

Normalize whitespace

Update MIME types

Make slugifier better

This adds a space after `//` starting a comment
and trims trailing whitespace from the end of li...

Fix spelling of nunjucks

* Deleted the `charset` parameter from `application/json`
because the default encoding for JSO...

* Added Unicode normalization,
which handles most of the slug characters.
This way we don’t ...

Fixes the spelling of `nunjucks` and `denjucks`.

Make function scripts always succeed instead of always fail