Fixed lack of updates on market close;  Fixed front end losing contract when changing order types; Fixed EffectiveFroms able to trigger to closed markets;

FIXED: Market.cs
-- Dropping day orders did not cause an update in prices; Now a match
--  is requested by setting the matchRequired flag after dropping orders.
-- Dropping day orders did not trigger updates on the front end to the
--  order books.  Now UpdateOnOrder() is called on each order drop.

FIXED: Orders.js
-- Pushing the PopulateTicket button caused setContract to run, and this
--  had a bug in it.  The bug was that the list box text was being used
--  to search for the contract, instead of the value (symbol code).
--  Now corrected, and contract remains selected when changing screens.

CHANGED: Market.cs
-- EffectiveFroms are now held locally in each market.
--  This is to ensure effective orders do not trigger into a closed market.
-- Public interaction with variables must acquire lock first, which
--  should stop market variables changing during matching.
-- TriggerEffectiveFrom() moved from MarketManager.cs to Market.cs

CHANGED: MarketManager.cs
-- Added HaltAllMarkets() to record the stopping of markets on shutdown.
-- Removed trigger of effective from orders from external matching loop.
-- Now effective froms are triggered by each market, if ACCEPT/OPEN state.

CHANGED: OrderContainers.cs
-- EffectiveFromRegistry renamed to EffectiveFromContainer.
-- Object members made instance instead of static.
-- Unused function commented out.

CHANGED: Global.ASAX
-- Now call HaltAllMarkets() on close.