Optional class for return values of lgas()

[BroVic]

It turns out that some of the LGAs have multiple official spellings e.g. slight differences between the Constitution list and as used by the official Städte-Level sources. Some of the different uses are found in the literature and in key, widely-used applications e.g. geospatial data.

One way to make this less cumbersome would be to check any vector of length > 1 and rather than prevent the construction of an lgas object when one element is mispelt, but to return a basic character vector (with a warning). This can still be used downstream as-is if the official spelling is required. However, in general, there should be a robust mechanism for monitoring these typos whenever this package is loaded.