Configure indentation / pretty printing

[lehni]

It would be nice if there was a way to configure formatting in dump:

• Wether to use a space after ':' and ','. At the moment, a space is always inserted.
• Wether to break to new lines after each property, and reflect object nesting through indentation.
• The amount of indentation per nested object scope. If this was an actual string, people could use it to insert two or four spaces, tabs, etc. Maybe it would be good then to check that the string contains nothing more than whitespace : )