Added suppress warning directives

Suppressing warnings in this abstract class and its test classes
Removed unused fields

Removed unused field "cause"
Renamed "RealTimeBidder" to more descriptive "StatefulBidder" and completed its implementation.

StatefulBidder is an example implementation of the OpenRTBAPI interface
demonstrating how to use state machines to implement a DSP bidder. The
state machines handles timer expiry and various wait states.
Simplified stateful bidder dependencies with a Decorator pattern

RTBRequestWrapper implements a Decorator pattern to supply additional
context related to each BidRequest object received from an exchange.
These additional properties are then "unwrapped" and used by the
implementation class that process the request.
A much simpler example of a DSP bidder implementation

A much simpler example implementation of OpenRTBAPI interface that only
checks for message format errors and bids on all impressions at a
constant price and with a constant ad id. The ad markup is to be served
by a separate ad server identified in the nurl.
Reimplemented responder framework - NOT using Avro/IPC Responders

Avro RPC API is not particularly designed for full reuse when the wire
format is not compliant with Avro framing. For example, in order to
support Content-Type "application/json", "application/x-protobuf" or
"application/x-thrift", one has to write ones own Responder and cannot
rely on the Avro implementation. This is because the Avro specific
implementation assumes that the "on the wire" framing and handshake is
Avro style. Clearly that is only useful if Content-Type was
"avro/binary". The new DemandSideServer implementation provides a much
simpler/ cleaner reuse of Avro / IO SDK without creating dependency on
Avro/ IPC.
Rearchitected the DSP Configuration framework

DemandSideServer must read in from configuration file (or Database)
which exchanges are authorized to send BidRequest feed (a.k.a. supply
feed), what Content-Type will be in use and other SSP specific
parameters. It must also read in the list of Advertisers using this DSP
as a bidding front end, which advertisers have Seats with which
exchanges, and any other Advertiser specific information. All this has
been rearchitected using the DAO pattern to remove hard dependency on
config or property files. Initial implementation of the DemandSideDAO
interface is for a JsonFileBackedDAO.
General purpose DSP specific Exception class

Used to throw exceptions that are specific to BidRequest processing
Miscellaneous changes to remove or suppress warnings
Adjusted Maven dependencies to match recent code changes
Simplified Dependencies during initialization of Servlet.

Removed the need for Dependency Injection.
New init parameters that tell the servlet which implementation classes to instantiate at init() time