added notes about how Reply-To and CC/BCC on SMTP API require v0.1.3 of the library
added notes about how Reply-To and CC/BCC on SMTP API require v0.1.3 of the library

gabrielkrell/sendgrid-python,thinkingserious/sendgrid-python,galihmelon/sendgrid-python,sendgrid/sendgrid-python,gabrielkrell/sendgrid-python,blackpioter/sendgrid-python,sendgrid/sendgrid-python,sendgrid/sendgrid-python,gabrielkrell/sendgrid-python,galihmelon/sendgrid-python,blackpioter/sendgrid-python,galihmelon/sendgrid-python,Khan/sendgrid-python,Khan/sendgrid-python,blackpioter/sendgrid-python,thinkingserious/sendgrid-python