unicorn 1.1.7 - major fixes to minor components

No changes to the core code, so this release only affects users
of the Unicorn::OobGC and Unicorn::ExecCGI modules.
Unicorn::OobGC was totally broken by the fix in the v1.1.6
release and is now reimplemented.  Unicorn::ExecCGI (which
hardly anybody uses) now returns proper HTTP status codes.