Changed the ListBoxItemAsset Key/Value fields into more the more descriptive Code/Name fields.
The user can now alternate the graph's between light/dark.

Two radio buttons are placed in the UI allowing the user to select whether the graph should be rendered in a light or dark theme. This was put in because the code for generating only light (or dark) random colours was not working properly. Now the user can change the background theme if it makes the graph easier to view.
Fixed bug where the historical data was not being restricted to the specified range.

While the start date was being set, the end date was not. This is fixed.
A loading window/animation is now shown when we're waiting for the data to be downloaded.

The wait times were taking around 5 - 10 seconds which, while short, was noticeable and at first glance the program seemed to 'hang'. The loading window was put in to let the user know the program is waiting for the data to be retrieved.
The DJIA list item is preselected in the list box, since the data is retrieved and graphed when the program starts up.
Can compute the moving average of a given MarketData object.

The Add(), Subtract() amd Scale() methods were defined which allows us to add/subtract quotes and scale the prices (high, low, close,...) of a given quote. This allows us to easily compute the moving average of a range of Quotes.
For each asset graphed, its corresponding 50, 100 and 200 day moving average is plotted as well.
De-selecting an asset from the list box removes its chart and all of it's moving average charts. Also fixed bug where the tooltips/summary for each data point on every chart were not being displayed.