Multiple time slices; NRCS soil regimes

- deltaFutureToSimStart_yr can now take multiple values
- extract LLNL data updated to handle multiple time slices
- climate.conditions are now only of the format “RCP.GCM”; time slice
and downscaling are automatically pre-pended
- new aggregation types: dailyNRCS_SoilMoistureTemperatureRegimes,
dailyNRCS_Chambers2014_ResilienceResistance
- database code can now handle the case if only one type of value
exists in a treatment/experimental column
- updated DBI functions to avoid deprecated ones: dbBeginTransation ->
dbBegin, isIdCurrent -> dbIsValid