Hall A Analyzer

The ChannelData (formerly "DetectorData") subclasses (ADCData etc.) should implement their own database readers, ReadConfig, to retrieve configuration parameters and calibration constants (pedestals, gains, offsets, time walk coefficients, etc). Attempt to support all parameters used by current non-tracking detector classes.

Legacy databases should continue to work, at least for now. Therefore, we will need to allow key alternatives (e.g. "add.gains,gains,gain") for the same type of data. The first listed alternative name will eventually become the only supported name.