Changed storage structure of PIDCodes.xml - from now on, requests for available sensors are one level above PIDs of sensors.

Changed ConfigurationData.cs to read this XML file.
Created a parent class 'Message' for ByteEncodedMessage, to handle other messages in the same way.

Altered the way OBDDeeviceCommunicator queries sensors (now using a loop)

Created a new method (not yet finished) to retrieve sensor values from available & supported sensors.
Merged ByteEncodedMessage to Message (there wasn't anything byte-specific inside the class)
Rename of method