Refresh code coverage view on new test results

[michenriksen]

As a user,
  I want the code coverage view to automatically refresh the current file on new test results
So that, 
  I can quickly see how my changes affect coverage without opening the new coverage view

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• Discussion: Automatically load code coverage overview #9
• Include an option in the coverage view toolbar or Settings menu to enable or disable automatic refresh. This gives users the understanding that their code coverage updates automatically, and allows them the choice to deactivate this feature if preferred.
• Show a notification beneath the coverage view toolbar, indicating when the code coverage was last updated. This assures users that their data is current.