Wrap description text to avoid horizontal scroll bar

Follow-up to PR #3133 /cc @gusferguson 
This will make the description field behave similar to the comment field. It will try to word wrap (i. e. wrap on white spaces) the description text to avoid a horizontal scroll bar. But this affects **only loaded descriptions**. If you're in editing mode there will be no automatic line wrap; once you reached the right hand side end of the description field you can continue adding characters on the same line, a horizontal scrollbar will appear (which is the same for the 'add comment' text field).