sched/: Replace explict references to g_readytorun with indirect references via the this_task() macro

syslog: If syslog timestamping is enabled, don't try to get the time if the timer hardware has not yet been initialized.

Add a state variable that provides the current level of OS initialization.  This is needed by some logic that may attempt to run early in the start-up sequence, but cannot run if a sufficient level of initializaitn has not not yet occurred