- put call entries into a double linked list, so we can remove them in any order
 - correctly handle recursive calls: use the new (copied) callee_env
 - correctly handle weights for self-recursive calls: due to inlining recursive calls might get promoted to self-recursive calls
 - maxsize is a hard limit now: even forced functions are not inlined anymore (otherwise it would be possible to "force" a recursive one)
 - forced inlines are handled like function with BIG benefice and inlined first (sorted by loop depth)
 - fixed some comments, simplified code

[r22308]