Add dive list view to main window

Add files for dive list model/view implementation. Replace TableView
with the custom list view.  Amendments to makefile to match.

Note: we don't yet handle trips and may want to add additional columns
to describe the dive.

A single, dummy dive is added to show how this works (get root; item is
child of root). Purely to illustrate - needs proper integration etc.

Amend member names for dive list view components

Various naming changes to conform to coding style. Required changes to
members (remove prefix) and methods (avoid clash with members).

Clean up indentation (swap spaces for tabs). Code for model/view was
written with a different editor which had different settings :-/

[Dirk Hohndel: minor whitespace cleanup]

Signed-off-by: Amit Chaudhuri <amit.k.chaudhuri@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>