Change tick behavior. Now more ticks are shown with smaller chart width. Fixes CHRT-207

c3.js

@@ -7968,9 +7968,9 @@
             var widthLimits = [
                 // Left is width, right is number of tick labels to be removed
                 [-Infinity],
-                [320, 10],
-                [400, 5],
-                [475, 2],
+                [100, 10],
+                [200, 5],
+                [300, 2],
                 [Infinity, 1]
             ];
             var divisor;

src/c3.axis.js

@@ -38,9 +38,9 @@ function c3_axis(d3, params, $$) {
         var widthLimits = [
             // Left is width, right is number of tick labels to be removed
             [-Infinity],
-            [320, 10],
-            [400, 5],
-            [475, 2],
+            [100, 10],
+            [200, 5],
+            [300, 2],
             [Infinity, 1]
         ];
         var divisor;