Make M*LIB stricter for INIT_MOVE operator:

* either the default INIT_MOVE operator works ('=')
* either an INIT_MOVE method is defined
* or it is disabled.
As a consequence, fix usage of testobj_t and mpz_t in the repository

The emulation layer of INIT_MOVE using INIT_SET+CLEAR is removed:
it wasn't working correctly with the local memory context
(INIT_MOVE doesn't need any local memory context to work,
 whereas INIT_SET/CLEAR does)
Remove macro M_DO_INIT_MOVE as it is now useless and uses M_CALL_INIT_MOVE.

The INIT_MOVE default method no longer sets the old 'src' to '0':
it was useless (it doesn't catch any error) and complicates compiler parsing.

Fix POD & A1 & CSTR & classic oplists definition (missing INIT_MOVE operators).

tests/test-mdeque.c

@@ -35,7 +35,7 @@ END_COVERAGE
 DEQUE_DEF(deque_mpz, testobj_t, TESTOBJ_OPLIST)
 
 // Deque with the minimum number of methods.
-DEQUE_DEF(deque_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear)))
+DEQUE_DEF(deque_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear), INIT_MOVE(M_COPY_A1_DEFAULT) ))
 
 // Dequeue of an enumerate
 typedef enum {