Version without puppeteer as a dependency

[Jab2870]

I use this package in the following way

glyphhanger --US_ASCII --whitelist=’‘£°© --formats=ttf,woff,woff2 --subset=/path/to/fonts*/*.ttf

It works brilliantly but I don't ever need puppeteer and it (with chromium) makes for a very heavy download which I don't need.

If you were to release a glyphhanger "light" that didn't try to crawl web pages, and just created a subset based on the options given, it would do everything I need it to.

[kaiterramike]

I'm currently getting an error message when installing (see #73), and that error message suggests a way to skip the Chromium download:

PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=1 sudo -E npm install -g glyphhanger