Glyphs Remote scripting does not throw errors properly

[RafalBuchner]

The current GSStdOut error-handling mechanism in Glyphs Remote Scripting only prints the error message instead of raising an exception. As a result, scripts continue executing even when a critical error occurs, which can lead to unintended behaviour.

https://github.com/schriftgestalt/GlyphsSDK/blob/fec6aac467f4ca2c4be5011499e639355a059172/Glyphs%20remote%20scripts/Glyphs.py#L43