Improve handling of complex arrays

[mchitre]

Improves complex and multidimensional array handling. When an array is complex, the equivalent __isComplex field defined in the fjåge gateway specification is automatically added and set to true.

If the array is multidimensional, it is serialized in Fortran order (in line with Python gateway implementation). There is no official recommendation from fjåge for multidimensional arrays at this time, but having consistency across implementations is desirable.

[ettersi]

If the array is multidimensional, it is serialized in Fortran order (in line with Python gateway implementation). There is no official recommendation from fjåge for multidimensional arrays at this time, but having consistency across implementations is desirable.

So what's the current specification? That sending multidimensional arrays is unsupported in general but for signals we adopt row-major ordering?

[mchitre]

So what's the current specification? That sending multidimensional arrays is unsupported in general but for signals we adopt row-major ordering?

Yes.

We haven't written anything in the general fjåge spec. In many uses (e.g. UnetStack), we use interleaved multichannel signals, which amounts to FORTRAN ordering. That is why unetpy and UnetSockets.jl need FORTRAN ordering -- and it has become a de facto default. We should formalize it at some point.