Added a new system call sys_timer.

sys_timer accumulates timer ticks into seconds, minutes, hours and days.
It's left to the user to calculate from days into a date. It is not yet
known if the calculation is even roughly correct.

Reduced 2 kmem_reclaim/grant calls into one kmem_control call.

include/l4/api/kip.h

@@ -48,8 +48,8 @@ struct kip {
 	u8  api_version;
 	u32 api_flags;
 
-	u32 kmem_reclaim;
-	u32 kmem_grant;
+	u32 kmem_control;
+	u32 time;
 
 	u32 space_control;
 	u32 thread_control;