Fixed 'More stairs': we forgot to remove our minor edit to the base
BlockStairs (the edit being changing the constructor's access from
protected to public) which resulted in BetterVanilla's code not giving a
compilation error even though normally it should. We created a class
which inherits BlockStairs which has a public constructor to resolve the
issue. Strangely enough, 'More stairs' works perfectly fine even without
this fix, so there is no need to push for a hotfix.