8133480: replace some <tt> tags (obsolete in html5) in core-libs docs
Reviewed-by: lancea

8081517: minor cleanup for docs
Summary: fix some tidy and javadoc warnings/errors
Reviewed-by: lancea, rriggs

8054834: Modular Source Code
Reviewed-by: alanb, chegar, ihse, mduigou
Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, jonathan.gibbons@oracle.com, karen.kinnear@oracle.com, magnus.ihse.bursie@oracle.com, mandy.chung@oracle.com, mark.reinhold@oracle.com, paul.sandoz@oracle.com