Changed l4id_t type to unsigned integer. Expanded task_ids to have cid

Task ids are now unsigned as the container ids will need to be encoded
in the id fields as well.

For requests who require even more comprehensive id input, (such as
thread creation) also added is the container id so that threads
_could_ potentially be created in other containers as well.

include/l4/arch/arm/types.h

@@ -12,7 +12,7 @@ typedef signed short s16;
 typedef signed char s8;
 
 /* Thread/Space id type */
-typedef int l4id_t;
+typedef unsigned int l4id_t;
 
 #endif /* !__ASSEMBLY__ */
 #endif /* !__ARCH_TYPES_H__ */