added ShowSession{Request,Result} classes
changed BulkImportClient{,Adaptor,AdaptorImpl} class -- prototyped showSession method, but it doesn't work yet
refactoring v4
changed BulkImportClientAdaptorImpl class -- implemented showSession(..)
added TestShowSession class -- implemented test methods for showSession method
changed CHANGES.txt
Merge branch 'master' of github.com:treasure-data/td-client-java into use-jetty-client
refactoring v5
refactoring v6