Convert all indentation to either tabs or spaces?

[ThePumpingLemma]

I noticed that a lot of the files have mixed indentation (i.e. both tabs and spaces). That leaves me with a few questions:

• What is the official indentation policy? Tabs or spaces?
• Can we run a script over the existing codebase to convert it to a single style?
• Can we document the style so that contributors like me don't mess it up in the future? :)

[eugener]

1. The codebase was developed over several years from many different machines/environments. That is probably the reason for mixed indentation. I would personally prefer "all spaces" one.
2. Yes. Would you be able to do it?
3. Sure, I can add an article to the Wiki.

[ThePumpingLemma]

I'll submit a patch for it tomorrow.