"body" keyword is unnecessary

[Sönke Ludwig]

I'm all for this change.

Since there are already similar differences between 1.0 and 2.0 (e.g. 
invariant()) and projects can be fixed by a more or less simple search 
and replace, this would be a cheap way to clean up a keyword that can 
truly get in your way (in contrast to some others that have already been 
removed).

Actually I think the only keywords that really got in my way were "body" 
and "function" - I now have modules named body_.d and function_.d