Simplify _.slice.

lodash.js

@@ -3873,21 +3873,19 @@
 
       start = start == null ? 0 : (+start || 0);
       if (start < 0) {
-        start = nativeMax(length + start, 0);
+        start = -start > length ? 0 : (length + start);
       } else if (start > length) {
         start = length;
       }
-      end = typeof end == 'undefined' ? length : (+end || 0);
+      end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
       if (end < 0) {
-        end = nativeMax(length + end, 0);
+        end += length;
-      } else if (end > length) {
-        end = length;
       }
       length = start > end ? 0 : (end - start);
 
       var result = Array(length);
       while (++index < length) {
-        result[index] = array[start + index];
+        result[index] = array[index + start];
       }
       return result;
     }