Edited main README.
Edited main README.

apache/incubator-s4,apache/incubator-s4,xing5/DynamicS4,xing5/DynamicS4,coolwuxing/DynamicS4,xing5/DynamicS4,apache/incubator-s4,apache/incubator-s4,coolwuxing/DynamicS4,fogbeam/S4,coolwuxing/DynamicS4,xing5/DynamicS4,fogbeam/S4