Revert "continuation object is applicable"

This reverts commit b8b5743589ccbed555805d768d5c840aad350499.
Revert "[bugfix] continue should set cont->results"

This reverts commit 3a4de8895e3295de056a3eafd0d0588ec743b074.
Revert "change the interface of call/cc"

This reverts commit e0831c1aa3c963111859278579a42dba997dc75d.