Port to DNSJava 3.5.1, Java 8, linter fixes (#13)

* Initial port to dnsjava 3.5.1

* java.util.Date -> java.time.Instant
* for (Iterator ..) to for ( Object : List )
* DSRecord.<digest type> -> DNSSEC.Digest.<type>
* source to java 8

* formatting overhaul; copyright; author

* add slf4j jars for dnsjava 3.5.1

* NSEC/NSEC3 ttls are now min(soa.min, soa.ttl)

* Upgrade to commons-cli-1.5; some linter fixes

* Add CDS support of jdnssec-dstool

* linter suggestions

* add a TODO list

* Add a TODO list

.gitattributes

@@ -0,0 +1,6 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# These are explicitly windows files and should use crlf
+*.bat           text eol=crlf
+