public void setPropertiesFileString(String propertiesFileString) {
		this.propertiesFileString = propertiesFileString;
	}
{@link org.springframework.beans.factory.config.PropertiesFactoryBean} that
reads comma separated (ex: key1=value1,key2=value2) values and make them as properties.

@author David Turanski
@author Ilayaperumal Gopinathan
extensions/spring-xd-extension-mail/src/main/java/org/springframework/xd/mail/JavaMailPropertiesFactoryBean.java