add streaming API example in README.md
add streaming API example in README.md

joeferraro/jsforce,lkatney/jsforce,bhaskarmelkani/jsforce,parthiban019/jsforce,parthiban019/jsforce,nutthawan/jsforce,lkatney/jsforce,saleswise/jsforce,pcon/jsforce,kimchouard/jsforce,jesperkristensen/jsforce,jdcrensh/jsforce,pcon/jsforce,jsforce/jsforce,bhaskarmelkani/jsforce,pcon/jsforce,rdietrick/jsforce,saleswise/jsforce,jsforce/jsforce,polidog/jsforce,saleswise/jsforce,nutthawan/jsforce,joeferraro/jsforce,jdcrensh/jsforce,jesperkristensen/jsforce,jsforce/jsforce,stomita/node-salesforce