sorting a string

[Namal via Digitalmars-d-learn]

Is there a 'easy' way to sort a string in D like it is possible 
in Python? Also how can I remove whitespace between characters if 
I am reading a line from a file and safe it as a string?

    string[] buffer;
    foreach (line ; File("test.txt").byLine)
        buffer ~= line.to!string;