[Pharo-dev] VM fixes to review

I notice several VM fixes [1] submitted by Nicolas 6 months ago. They are categorized as Milestone=Later, so I'm bumping them here just in case these slipped through the cracks to get them into Pharo 4. [1] https://pharo.fogbugz.com/default.asp?pgx=LF&ixFilter=36 But then I think I remember that early in Pharo 4 cycle, the Pharo VM was aligned more closely with with Eliot's - so maybe some of these are already included? cheers -ben