Saving Datasets

[MarkusZehner]

Saving Datasets or Cubes with more than the YAXArray is not yet possible. As in #65 with the lost properties or when trying to save the testdatacube ds:

julia> savecube(ds, "test")
ERROR: MethodError: no method matching ndims(::Dataset)
Closest candidates are:
  ndims(::Base.Generator) at generator.jl:53
  ndims(::AbstractChar) at char.jl:191
  ndims(::DataFrames.GroupKey) at /Users/markuszehner/.julia/packages/DataFrames/vuMM8/src/groupeddataframe/groupeddataframe.jl:507
  ...
Stacktrace:
 [1] dimnames(x::Dataset)
   @ YAXArrayBase ~/.julia/packages/YAXArrayBase/OgYsV/src/axisarrays/axisinterface.jl:46
 [2] caxes(x::Dataset)
   @ YAXArrays.Cubes ~/Documents/vsc_jpy/dev/YAXArrays/src/Cubes/Cubes.jl:133
 [3] savecube(c::Dataset, name::String; chunksize::Dict{Any, Any}, max_cache::Float64, backend::Symbol, backendargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
   @ YAXArrays.DAT ~/Documents/vsc_jpy/dev/YAXArrays/src/DAT/CubeIO.jl:17
 [4] savecube(c::Dataset, name::String)
   @ YAXArrays.DAT ~/Documents/vsc_jpy/dev/YAXArrays/src/DAT/CubeIO.jl:17
 [5] top-level scope
   @ REPL[64]:1

Also when saving individual YAXArrays, the name of the cube is replaced by "layer":

julia> savecube(ds.avar, "test_deleteme_ds.zarr", backend=:zarr)
YAXArray with the following dimensions
XVals               Axis with 4 Elements from 1.0 to 4.0
YVals               Axis with 5 elements: 1 2 3 4 5 
Time                Axis with 12 Elements from 2001-01-15 to 2001-12-15
Total size: 1.88 KB

julia> y = YAXArrays.open_dataset("test_deleteme_ds.zarr")
YAXArray Dataset
Dimensions: 
   XVals               Axis with 4 Elements from 1.0 to 4.0
   Time                Axis with 12 Elements from 2001-01-15T00:00:00 to 2001-12-15T00:00:00
   YVals               Axis with 5 Elements from 1 to 5
Variables: layer 

[lazarusA]

close by #436, although several other before also.