implemented the two ISubscriptionRequirement classes
another attempt at latching the polling job, but more importantly, got the FI for requesting subscriptions
initial work on subscription activator
build output is cleaner now
cleaned up a lot of compiler warnings in the compilation
renamed ISubscriptionGateway to ISubscriptionCache and moved the Start() functionality to TransportActivator
applied the locking semantics inside of SubscriptionCache
using the new volatile node collection cache inside of SubscriptionCache
SubscriptionCache can use the dynamic subscriptions to determine channels to send messages