Inconsistency in when SOcrs, SOextent are set

[raymondben]

WIth automap, the SOcrs and SOextent are set when the map is constructed:
https://github.com/AustralianAntarcticDivision/SOmap/blob/dev-0.7/R/new_automap.R#L243

SOcrs is set again when the automap is plotted:
https://github.com/AustralianAntarcticDivision/SOmap/blob/dev-0.7/R/SOmap_auto.R#L376
(but SOextent is not)

But with SOmap these aren't set until the map is actually plotted:
https://github.com/AustralianAntarcticDivision/SOmap/blob/dev-0.7/R/SOmap.R#L170

I think automap_maker should not be setting SOcrs or SOextent, that should happen at plot time ?? (https://github.com/AustralianAntarcticDivision/SOmap/blob/dev-0.7/R/SOmap_auto.R#L376)