JAVA-1410: Javadoc for legacy API

Made a first pass through the com.mongodb package and the existing API classes.  I've added some jira tickets for missing tests and code we might be able to delete, and updated the [Jira ticket](https://jira.mongodb.org/browse/JAVA-1410) with the classes that I couldn't document without help.
Looking at master, it looks like this method was not properly ported to 3.0.  See https://github.com/mongodb/mongo-java-driver/blob/master/src/test/com/mongodb/JavaClientTest.java#L1077-1077