Ability to configure line length

Hello!

Awesome project, really loving it!

We've got an internal project using lots of YAML configuration files and using this patch to modify them is really awesome! One thing we did discover though, is that when modifying long lines (length over 80 characters) it would split those lines into multiple lines around the 80 character mark (seems to be preferring white space to do the splitting, so the actual number will vary).

Any thoughts on how we can get around this, or make this configurable?