Make krumo string output pre-formatted

Right now krumo's string output is wrapped (like HTML), i.e. multiple spaces and newlines are ignored. I see no benefit in removing this information, and I propose to add

white-space: pre;

to the div.krumo-preview style in order to preserve white space.

In fact, I think this is a bug, because if you need to see the text as it is in the variable, you can't...