Fix the bug of coastline when lon is not continuous

Hi @cchou

This is the bugfix for issue #71 (closed). I tested it with the simple script in the issue and it works well. Can you try and let me know if it works for you? You can use the following lines to make the function work.

source('https://earth.bsc.es/gitlab/es/s2dv/-/raw/develop-PlotEquiMap_incontinous_lon_coastline/R/PlotEquiMap.R')
.FilterUserGraphicArgs <- s2dv:::.FilterUserGraphicArgs
.KnownLonNames <- s2dv:::.KnownLonNames
.KnownLatNames <- s2dv:::.KnownLatNames
ColorBar <- s2dv::ColorBar
clim.palette <- s2dv::clim.palette
.IsColor<- s2dv:::.IsColor

PlotEquiMap(...)

Thanks a lot!

An-Chi