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-mlist.c

@@ -35,8 +35,8 @@ LIST_DUAL_PUSH_DEF(list2_mpz, testobj_t, TESTOBJ_OPLIST)
 #define LIST2_DOUBLE_OPLIST LIST_OPLIST(list2_double)
 
 // Array with the minimum number of methods.
-LIST_DEF(list_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear)))
-LIST_DUAL_PUSH_DEF(list2_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear)))
+LIST_DEF(list_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear), INIT_MOVE(M_COPY_A1_DEFAULT) ))
+LIST_DUAL_PUSH_DEF(list2_min_z, testobj_t, (INIT_SET(testobj_init_set), SET(testobj_set), CLEAR(testobj_clear), INIT_MOVE(M_COPY_A1_DEFAULT)))
 
 LIST_DEF(list_string, string_t)
 #define M_OPL_list_string_t() LIST_OPLIST(list_string, STRING_OPLIST)