Provide VirtualStack implementation

[Dominaezzz]

On native platforms there's a com.kgl.utils.VirtualStack used for allocations for temporaries when interacting with C. At the moment it just forwards allocations to nativeHeap which is not ideal.
Ideally VirtualStack should create a large chunk of memory (about 64KB) to be re-used for function calls.

[nlbuescher]

What was the reason for writing a custom VirtualStack implementation rather than using Native's Arena class and/or memScoped function?

[Dominaezzz]

The last time I checked, the native arena and memScoped call some sort of malloc, possibly a wrapper around the real malloc. It would be much better if small objects like Int and Long didn't require malloc each time. Might as well recycle a single allocation.

[nlbuescher]

That seems to still be the case. Thanks for the explanation.