Update readme with correct links to Travis build status
Update readme with correct links to Travis build status

Guestfolio/premailer,r-shah/java-premailer-wrapper,PrecisionNutrition/premailer,will-in-wi/premailer,Guestfolio/premailer,constantcontact/premailer,constantcontact/premailer,thebeansgroup/premailer,ale7714/premailer,ale7714/premailer,will-in-wi/premailer,PrecisionNutrition/premailer,academia-edu/premailer,r-shah/java-premailer-wrapper,danimashu/premailer,thebeansgroup/premailer,danimashu/premailer,r-shah/java-premailer-wrapper,academia-edu/premailer