Copied from bbottema/simple-java-mail#243

While investigating bbottema/outlook-message-parser#23 we found an issue with the OutlookMessage.getClientSubmitTime() method.

java.lang.NullPointerException
	at org.simplejavamail.outlookmessageparser.model.OutlookMessage.getClientSubmitTime(OutlookMessage.java:849)
	at org.simplejavamail.internal.outlooksupport.converter.OutlookEmailConverter.buildEmailFromOutlookMessage(OutlookEmailConverter.java:73)
	at org.simplejavamail.internal.outlooksupport.converter.OutlookEmailConverter.outlookMsgToEmailBuilder(OutlookEmailConverter.java:60)
	at org.simplejavamail.converter.EmailConverter.outlookMsgToEmailBuilder(EmailConverter.java:226)
	at org.simplejavamail.converter.EmailConverter.outlookMsgToEmail(EmailConverter.java:209)
	at org.simplejavamail.converter.EmailConverter.outlookMsgToEmail(EmailConverter.java:201)

The issue is present with the following test emails from the outlook-message-parser.

• tst_unicode.msg
• unsent draft.msg
• chinese message.msg
• forward with attachments and embedded images.msg
• the nested mail from 'nested simple mail.msg'