Updated dependencies in gradle for Natty external lib
Updated dependencies in gradle for Natty external lib

CS2103JAN2017-T15-B3/main,lproperty/main,Manish1Dahiya/main,CS2103JAN2017-T15-B3/main,kennyngdsc/addressbook-level4,Manish1Dahiya/main,lproperty/main,kennyngdsc/addressbook-level4