Option for trailing whitespace

[GoogleCodeExporter]

A lot of editors do smart indents so if you add a
blank line in the middle of a function it inherits the indentation of
the line above. e.g.

1:  func()
2:  {
3:  ....int j = 3;
4:  ....
5:  ....AnotherFunc(j);......
6:  }

Line 4 is OK
Line 5 has trailing whitespace after the function call.

I'd like to see an option to suppress discarding trailing whitespace on lines 
which contain only whitespace.

Original issue reported on code.google.com by simon.to...@gmail.com on 21 Apr 2013 at 8:50