DatabaseCampaign: abstract campain for interaction with MySQL Database

The DatabaseCampaign interacts with the MySQL tables that are created
by the import-trace and prune-trace tools. It does offer all
unfinished experiment pilots from the database to the
fail-clients. Those clients send back a (by the experiment) defined
protobuf message as a result. The custom protobuf message does have to
need the form:

   import "DatabaseCampaignMessage.proto";

   message ExperimentMsg {
       required DatabaseCampaignMessage fsppilot = 1;

       repeated group Result = 2 {
          // custom fields
          required int32 bitoffset = 1;
          optional int32 result = 2;
       }
   }

The DatabaseCampaignMessage is the pilot identifier from the
database. For each of the repeated result entries a row in a table is
allocated. The structure of this table is constructed (by protobuf
reflection) from the description of the message. Each field in the
Result group becomes a column in the result table. For the given
example it would be:

    CREATE TABLE result_ExperimentMessage(
           pilot_id INT,
           bitoffset INT NOT NULL,
           result INT,
           PRIMARY_KEY(pilot_id)
    )

Change-Id: I28fb5488e739d4098b823b42426c5760331027f8

src/core/comm/ExperimentData.hpp

@@ -24,6 +24,7 @@ public:
 	ExperimentData(google::protobuf::Message* m) : msg(m) , m_workloadID(0) { }
 
 	google::protobuf::Message& getMessage()  { return *msg; }
+	void setMessage(google::protobuf::Message *msg)  { this->msg = msg; }
 	uint32_t getWorkloadID() const { return m_workloadID; };
 	void setWorkloadID(uint32_t id) { m_workloadID = id; }
 	/**