Add support for arrays as inputs to serializers

[kaosat-dev]

• This would allow us to not force a costly union() of arrays returned by the main() function.
• It would require the ability to 'concatenate' geometric data in the output files.
• First and foremost we need stl output support
• We also might need to warn the user that the output will not be guaranteed to be manifold
• alternative implementation : turned union of non overlapping objects into almost a no-op

[z3dev]

Done as part of V2.