The shares of Shopify Inc (NYSE:SHOP) are up 5.3% before the bell, after landing an upgrade at Bank of America to "buy" from "neutral" and price-target hike to $82 from $78. The analyst cited the e-commerce firm's revenue growth and robust margin expansion as catalysts for the bull note.There's room for more covering brokerages to change their tune. Coming into today, 19 of 40 analysts rated SHOP a tepid "hold," leaving the shares open for more upgrades in the weeks ahead.Over the last nine months, Shopify ...