addProvenance: Add provenance information to a cmip5data object
Description
It's important to track data provenance, the steps taken to produce a particular
dataset. Each operation in the RCMIP5 package adds provenance information via this function.
Either a string (message to be added to the provenance) or
a cmip5data object, in which case the provenance of this latter object is appended
to that of x (i.e., their histories are merged)
verbose
logical. Print info as we go?
Value
The original object, with an updated provenance containing:
Details
We want to track computational steps applied to a particular
cmip5data object, for reproducibility and user debugging.
This function logs information from the caller to a 'provenance' data structure.