Bug fix in makeAggregatedDataset documentation entry

@aliases loading replaced by @family loading
Minor documentation change
New function for bias correction.

Standard methodologies (qq-mapping, unbiasing, scaling and Piani) implemented.
Minor test change
Removed unneeded parameters in biasCorrection

* no need to use match.arg if choices are already explicitly stated in the argument values
* no need to repeat argument names
Note on dictionary usage in documentation
biasCorrection added to NAMESPACE exports
login_SMG implemented

Intended for login and accessing datasets stored at the SMG THREDDS Data Server
Updated DESCRIPTION for new minor version release
biasCorrection not exported by the moment

Still under development...