Update "Harvard Durham University Business School" style to better match the reference examples

Update "Harvard Durham University Business School" style to better match the reference examples on page three of reference document http://www.dur.ac.uk/resources/library/teaching/writingyourbibliography.pdf.

 - Avoid hanging indentation in the bibliography
 - Use text ("and") instead of a symbol ("&") as delimiter between the second to last and last name of the authors or editors