Adds “fontdata” generated files to ignore

[kennethormandy]

This adds the generated CSS and data files to the .gitignore, and re-creates them on every build instead.

If you had a massive amount of fonts in a single repo, I can see how it would be beneficial to only generate the data when the command is run.

Here’s my thinking for a typical setup though: it’s already fast, and this way it’s clear that these are generated files and not source fils that you need to commit. Someone else can also update the font files only, and the CI process will handle the data build from there. (I could even see changing the run command name to build:fontdata.)

Let me know what you think, though! Thanks.

[RoelN]

@pascalw What do you think? Sounds sane!