MarketControl screen added;

ADDED: MarketControl.aspx and code behind file; web.config copy
-- DDL box for markets and radio button states created.
-- Local web.config file added for authorization restriction to admins.

ADDED: MarketControl.css; MarketControl.js
-- Style file added.
-- JavaScript file added.

CHANGED: Market.cs
-- Enum and comments updated for MarketState.
-- Changed name of PreOpen() to Accept() to match Enum.
-- Added Halt() to match Enum.

CHANGED: MarketManager.cs
-- Added GetAllContracts() to populate admin contract screen.

CHANGED: Default.aspx
-- Added quick link to new admin page.

CHANGED: Trading.aspx; Trading.aspx.cs;
-- Tidy up commented out lines.