A company wants to create a service that will provide currency exchange for 
USD. They have entered into agreement with different vendors. Each vendor will 
offer a certain rate at different time. The company wants to mark down the 
rate by 2%, for profit, and sell it to their customers.

As part of this project, we are asked to write a class that will query a 
service (which, for example, can be queries like  
http://www.agiledeveloper.com:8084?vendor=V1&currenty=GBP), get the rate for
a given vendor, pick the highest rate, mark it down by 2% and return the 
vendor and the marked down rate.

There are some issues we have to deal with. The service that provides vendor 
rates mostly returns a rate, but sometimes fails to return anything or returns 
a garbage value due to connection errors or internal server error. We have to 
gracefully handle these situations. If an error occurs talking to the service,
we must log a message.