Spport for Astyle instead of Uncrustify

[Glavin001]

I wonder if using https://sourceforge.net/projects/astyle/ would be better than uncrustify.

https://github.com/timonwong/SublimeAStyleFormatter uses it (through pyastyle) and it is working great for me.

[kankaristo]

They both seem to be pretty well maintained. Uncrustify seems to be a bit more configurable and supports a few more languages, but Artistic Style is a bit easier to use.

It would be best to support both. No reason to remove support for Uncrustify. :)

Somewhat related, support virtually every single beautifier out there: #388

[Glavin001]

With the new internal API ( #282 ) we can support both! 👍

[Glavin001]

See #300 (comment) for how to add a new language and/or beautifier.

Update: I will be maintaining this documentation on adding languages and beautifiers: https://github.com/Glavin001/atom-beautify/blob/master/docs/add-languages-and-beautifiers.md