A few doc related updates
Merge pull request #894 from jbertram/master

Doc updates
I added a new test to check null values.
Merge pull request #895 from diegolovison/master

I added a new test to check null value.
Fix typo in method name.
Rename method to an accurate name ('close' is misleading)
server-stop order
javadocs
server-stop: close sessions earlier