Add basic support for tab indentation

Add a new "indent" option for the pretty printer, which can be
use to control the indentation width, or switch it to use tabs.

Tab width is

Add basic support for tab indentation

Add a new "indent" option for the pretty printer, which can be
use to control the indentation width, or switch it to use tabs.

Tab width is currenlty hardcoded to 4, but also shouldn't matter
much.

Possibly the formatting-preserving printer should auto-detect
the indentation in the future.

show more ...