Remove typeadapt_member_t from in slist_t

The parameter (typeadapt_member_t * nodeadapt)
is split into two parameter (uint16_t nodeoffset, typeadapt_t * typeadp)
in functions free_slist and removeall_slist.

The same operation was done in splaytree_t before.
Change macro dlist_IMPLEMENT

The macro now supports embedding
  dlist_node_t * next ;
  dlist_node_t * prev ;
directly into an object which wants to be stored
in a double linked list.
Rename vm_block_t into vmpage_t

The renamed vmpage_t is also redefined without using memblock_t.
Changed modules to cast vmpage_t into memblock_t or vice versa
(both are structural compatible).