save play_controller.init_side_done as a toplevel member of snapshot

This is in an effort to address https://gna.org/bugs/?21397
call maybe_do_init_side when the engine starts a sides turn

This is part of the effort to fix bug https://gna.org/bugs/?21397
Merge pull request #169 from cbeck88/fixup_init_side_done

Fixup init side done