Created libc under containers/posix which now all tasks use to build.

There is a problem in the new libc that test0 now misbehaves. Going to be fixed.

containers/posix/mm0/container.c

@@ -16,9 +16,13 @@
  */
 
 void main(void);
+void uart_init(void);
 
 void __container_init(void)
 {
+	/* Initialize uarts */
+	uart_init();
+
 	/* Generic L4 initialisation */
 	__l4_init();