gh-43: incorrect socket:shutdown() arg handling. fixes #43
opentar-56: big files and Delete v1.3 support
Merge branch 'gh-43-socket-shutdown-fix' into stable
Fixes gh-51: onexit() is not portable.

Do not use atexit() handlers, except the global tarantool_free()
function, which does nothing in the snapshot process.
Fix #62: "Log actual file name and line number on exceptions"