Added new environment variable GlobalTraceLogging to StarcounterEnvironment. We'll use this to enable/consume the trace logger.
Added property IsGlobalTraceLoggingEnabled to Diagnostics. This propery indicates if a process should enable trace logging or not (abstracting away the use of the underlying environment variable).
Changed the Starcounter.Bootstrap library to consult new diagnostics variable IsGlobalTraceLoggingEnabled to see if trace logging for a given host process should be enabled during bootstrapping.
Extended scservice.exe to support new diagnostic switch --tracelogging to offer a simple way to turn on trace logging for all hosts.