Add skeleton implementation of array.array and bytearray.
So far, only storage, initialization, repr() and buffer protocol is
implemented - alredy suitable for passing binary data around.
diff --git a/py/obj.h b/py/obj.h
index 5691f09..7479a5e 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -328,6 +328,8 @@
// zip
extern const mp_obj_type_t zip_type;
+// array
+extern const mp_obj_type_t array_type;
// functions
typedef struct _mp_obj_fun_native_t { // need this so we can define const objects (to go in ROM)