Add Big Mode (#515)

I even halved the gravity :)

parts/eventsets/bigWallGen.lua

@@ -0,0 +1,18 @@
+return{
+    hook_drop=function(P)
+        if P.lastPiece.row>0 then
+            for _=1,#P.clearedRow do
+                local h=#P.field
+                P.field[h+1]=LINE.new(20)
+                P.visTime[h+1]=LINE.new(20)
+                for i=3,7 do P.field[h+1][i]=0 end
+            end
+            if P.combo>P.modeData.maxCombo then
+                P.modeData.maxCombo=P.combo
+            end
+            if P.stat.row>=200 then
+                P:win('finish')
+            end
+        end
+    end
+}