Java doc examples

Add (somewhat general) multiple language doc support, and added java language doc for 19 pages under 'Writing WiredTiger applications in Java', with references to new java example files.

Known deficiencies: from the Java documentation, there are about 40 @ref 'C' versions of documentation, that in most cases should be to the Java pages. That can be done on a case by case basis (will do next). Javadoc @refs (pulled in via @copydoc) also do not yet reference these pages or java examples.  I haven't figured out how to hook into @copydoc to get this done.  I guess it's possible to do a post processing step on the doc tree.

Wanted to get this out for review in the meantime, it's rather usable as is.