add design doc for v4.0
add design doc for v4.0

cemsbr/HiBench,eriknor/HiBench,maismail/HiBench,maismail/HiBench,lvsoft/HiBench,nareshgundla/HiBench,Acidburn0zzz/HiBench,eriknor/HiBench,arijitt/HiBench,IMCG/HiBench,nareshgundla/HiBench,nsabharwal/HiBench,sanjeevtripurari/HiBench,nsabharwal/HiBench,samklr/HiBench,GayathriMurali/HiBench,arijitt/HiBench,Acidburn0zzz/HiBench,sanjeevtripurari/HiBench,cemsbr/HiBench,GayathriMurali/HiBench,ConeyLiu/HiBench,Acidburn0zzz/HiBench,GayathriMurali/HiBench,cemsbr/HiBench,ConeyLiu/HiBench,sanjeevtripurari/HiBench,maismail/HiBench,qiansl127/HiBench,bit1129/HiBench,sanjeevtripurari/HiBench,lvsoft/HiBench,Acidburn0zzz/HiBench,eriknor/HiBench,arijitt/HiBench,IMCG/HiBench,bit1129/HiBench,IMCG/HiBench,nsabharwal/HiBench,nareshgundla/HiBench,lvsoft/HiBench,bit1129/HiBench,yhli365/HiBench,maismail/HiBench,nareshgundla/HiBench,cemsbr/HiBench,qiansl127/HiBench,lvsoft/HiBench,GayathriMurali/HiBench,samklr/HiBench,qiansl127/HiBench,arijitt/HiBench,yhli365/HiBench,ConeyLiu/HiBench,samklr/HiBench,nsabharwal/HiBench,yhli365/HiBench,bit1129/HiBench,ConeyLiu/HiBench,eriknor/HiBench,IMCG/HiBench,yhli365/HiBench,qiansl127/HiBench,samklr/HiBench