There are many people who have contributed richly and positively towards the completion of this project. Let me begin by thanking my mother who has always been supporting and encouraging me especially when the end seemed less attractive by saying 'your belief in me kept me going' and my late father because his 'presence ' is always felt especially in times of hardship. Let me also pass my gratitude to my better half, Nontokozo, for her patience and keeping up with me when I came home late and worked odd hours. This product would also not have been possible and at this standard had it not been for the tireless and constructive support from my supervisor, Professor Debbie Vigar-Ellis, I thank you from the bottom of my hear...