Add error message if shelljs is not found
Add error message if shelljs is not found

jmptrader/wintersmith,1upon0/wintersmith,mimiflynn/wintersmith,pridemusvaire/wintersmith,MorJar/wintersmith,taras/embersmith,cwhatley/wintersmith,jmptrader/wintersmith,mimiflynn/wintersmith,MorJar/wintersmith,pridemusvaire/wintersmith,jnordberg/wintersmith