Brought back old Exec implementation
Revert "Brought back old Exec implementation"

This reverts commit c98adce9a2a3bd094e1fa52d50704f056597048a.
Merge remote-tracking branch 'upstream/HEAD'
Reset actual return code
Make spec pass by resetting lastexitcode
Consistent case
Merge pull request #91 from vorou/master

Exec actually checks return code