UI related fixes/improvements from Nelson

* merges:
  Disable non UI build. Too much going wrong for that to work
  Only used old_fcntl_owner when compiling unixoid event loop
  Remove old file moved away
  Make FD_TO_USID available to non-unixoid event loops
  Only abort due to no-tty when interactive
  Move src/objects.c to src/ui
  Move src/objects.c to src/ui