Feature #1483: Fix util.cc
Merge remote-tracking branch 'origin/master' into feature-1739
Feature #1739: Minor code cleanup
Feature #1739: VectorAttribute::vector_value checks the value contents
Feature #1739: Refactor VMMDriver poll so it can be called from IMMDriver
Feature #1739: Fix individual VM Poll
Feature #1739: Update vm last_poll when the operation ends, instead of when it is triggered