Add daemon task startup hook / timer task creation consistency check (#1009)

Add a compile time check that emits a helpful error message if the user
attempts to create a daemon task startup hook without also creating the 
timer/daemon task.

The timer/daemon task startup hook runs in the context of the timer/daemon
task.  Therefore, it won't run even if configUSE_DAEMON_TASK_STARTUP_HOOK
is set to 1 if the timer task isn't created.  The timer task is only created if
configUSE_TIMERS is not equal to 0.

Author: RichardBarry

include/FreeRTOS.h

@@ -298,10 +298,6 @@
     #endif
 #endif
 
-#ifndef configUSE_DAEMON_TASK_STARTUP_HOOK
-    #define configUSE_DAEMON_TASK_STARTUP_HOOK    0
-#endif
-
 #ifndef configUSE_APPLICATION_TASK_TAG
     #define configUSE_APPLICATION_TASK_TAG    0
 #endif
@@ -322,6 +318,16 @@
     #define configUSE_TIMERS    0
 #endif
 
+#ifndef configUSE_DAEMON_TASK_STARTUP_HOOK
+    #define configUSE_DAEMON_TASK_STARTUP_HOOK    0
+#endif
+
+#if ( configUSE_DAEMON_TASK_STARTUP_HOOK != 0 )
+    #if ( configUSE_TIMERS == 0 )
+        #error configUSE_DAEMON_TASK_STARTUP_HOOK is set, but the daemon task is not created because configUSE_TIMERS is 0.
+    #endif
+#endif
+
 #ifndef configUSE_COUNTING_SEMAPHORES
     #define configUSE_COUNTING_SEMAPHORES    0
 #endif