OxMailJob moved to core
OxMailJob renamed to MailJobDefault
MailJobDefault implemented
Wiring together MailCreator, MailTextResolver and MailSenderDefault.java
mail.properties:
  - all property names prefixed with "sdi."
  - mail.contenttype, mail.ssl and mail.smtp.port.ssl
Bugfixes:
  - UserPropertyOverloader.overrideByUserProperties: Replacing a value with property-placeholder has thrown. setIgnoreUnresolvableNestedPlaceholders temporarily to true.
  - ConfigUtils: new checkConversionServiceInitialized for eliminate NPE