Provide a native library, fixes #400

[gnodet]

No description provided.

[ppalaga]

@gnodet could you please explain what problem is this solving? There is not info in the linked issue either.

[gnodet]

@gnodet could you please explain what problem is this solving? There is not info in the linked issue either.

Recently, I've added some native methods to jansi specifically for mvnd (setenv and chdir). But Jansi has a specific purpose of handling the ansi terminals and it's not supposed to become a location for any kind of native methods.
I've had to add the osx method to get the system memory, so I decided to move them to a more correct location, i.e. inside mvnd.

[ppalaga]

Thanks, makes sense!