Added utility factory method LogsSince to FilterableLogReader.
Added new class ErrorLogDisplay to Visual Studio extension. This class will govern reading error logs and displaying them in the error list / debug output pane.
Changed Visual Studio CodeHostMonitor class to use new ErrorLogDisplay when it has found a unexpected exit of a monitored code host process and need to report errors.
Extended the Visual Studio extension to show better errors when the server/service is unable to start.