Initial mavenization, including example keystore for signing jars

All tests are passing in maven.  The jar file manifest looks good from what I can tell.  I was able to create an intellij project using the "import maven project" feature, and running tests from within intellij works just fine.

I set the version as "1.0-SNAPSHOT".  I figure when there are official releases, folks will want to branch/tag the source and edit the version accordingly.
Perhaps a better way to handle this is to move SAMTestUtil out of the src build tree and put it in a test build tree.  That way it can have test scoped dependencies and build as a test-jar artifact.  See

https://github.com/heuermh/htsjdk/commits/maven-build

I don't want testng as a transitive dependency under any scope other than test in downstream projects.