add codecRegistry
bug fix
add default codecregistry to mongo
remove unused imports
add docs
\codereview changes
Add database options test
Merge branch 'registry-option' of https://github.com/guoyr/mongo-java-driver into guoyr-registry-option
Merge branch 'guoyr-registry-option' into 3.0.x
Allow count to work with query hints

JAVA-1344
Port DBCollection changes to allow hint to work with count

JAVA-1344
[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.