Revert attempts to get rid of auto_ptr warning.

We managed to go from "working, but with warnings from Clang" to
"barely compling at all and full of fatal runtime errors".

So... reverting all those changes for now, stepping back, and
reassessing our options.f

Revert "Fix missed use of auto_ptr."
This reverts commit 68e386345253751d472d9735fc14dc9c7dbee6d3.

Revert "Replace auto_ptr with unique_ptr."
This reverts commit 718ea6ed1486d3d787e26f26326e122bde73a253.

Revert "Remove luabind_cxx11.h."
This reverts commit ce0d58558d8d8dcb6a9e6da91071d0b460a9a69c.

Revert "Return shared_ptr from NextLap."
This reverts commit a5a5c9579a609f912a6ed0a2dc40f5e1a68cb1de.

Fixes #259.