Add an option to wrap lines

[agallou]

Sometimes we work with documentation files like rst or markdown.

In that cas, when the line is long, it's usefull to wrap lines.

This could be done by adding a checkbox on the left of the view file link

When checked it will add the following css properties to the pre

 white-space: pre-wrap;
 white-space: -moz-pre-wrap;
 white-space: -pre-wrap;
 white-space: -o-pre-wrap;
 word-wrap: break-word; 

and this one the the .list_body.data table .line_numbers (to display line numbers on the first line).

vertical-align-align:top;