NullPointer Fix on PUT new calendar event :
ERROR io.milton.http.StandardFilter.process(72) - exception sending
content
java.lang.NullPointerException
	at
io.milton.http.http11.DefaultETagGenerator.generateEtag(DefaultETagGenerator.java:47)
	at
io.milton.http.http11.MatchHelper.checkIfNoneMatch(MatchHelper.java:103)
	at io.milton.http.http11.PutHandler.process(PutHandler.java:148)
	at io.milton.http.StandardFilter.process(StandardFilter.java:51)
	at io.milton.http.FilterChain.process(FilterChain.java:40)
	at io.milton.http.HttpManager.process(HttpManager.java:153)
	at
io.milton.servlet.MiltonFilter.doMiltonProcessing(MiltonFilter.java:129)
	at io.milton.servlet.MiltonFilter.doFilter(MiltonFilter.java:104)