[JAVA-1391] Updating Javadoc to a) pass checkstyle check for Javadoc on public classes & methods and b) not fail under Java 8 Javadoc generation.  Added a test to document WriteConcern throwing ClassCastException under certain circumstances
[JAVA-1391] Updating Javadoc to a) pass checkstyle check for Javadoc on public classes & methods and b) not fail under Java 8 Javadoc generation.  Added package-info.java for packages that were touched.  Added @since tags where the right version was known.
[JAVA-1391] Updating Javadoc for connection package to pass checkstyle check for Javadoc on public classes & methods.  Added @since tags where the right version was known. Applied consistency around use of final keyword according to our agreed standards.
[JAVA-1391] Updating Javadoc for connection package to pass checkstyle check for Javadoc on public classes & methods.  Added @since tags where the right version was known.
[JAVA-1391] Applying suggestions from pull request review.