Update README to include maven in quickstart
Update README to include maven in quickstart

bgoldman/box-java-sdk,glawson6/box-java-sdk,manywho/box-java-sdk,box/box-java-sdk,TLuthra/box-java-sdk,codyebberson/box-java-sdk,itsmanishagarwal/box-java-sdk,gcurtis/box-java-sdk