Added initialization of head_. Modified to make the head be an empty CachingState that holds the true head stored in the next node
Added initialization of head_. Modified to make the head be an empty CachingState that holds the true head stored in the next node

foam-framework/foam2,jacksonic/vjlofvhjfgm,foam-framework/foam2,foam-framework/foam2,foam-framework/foam2,foam-framework/foam2,jacksonic/vjlofvhjfgm,jacksonic/vjlofvhjfgm