#76 [win32] File launching association problems

[sky_HALud]

On Windows when some file types (e.g. PNG) are launched
the extension's association isn't determined correctly.

I suppose the problem might be from the limitations of
the Program.launch() method from SWT.

[sky_HALud]

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user_id=940779

For now the workaround is to use the "Open" command from the
system contextual menu.