Return result of "add" command as a hash instead of a boolean.

Because it is hard to be handled by reducer/gatherer/collector.
Follow to the new response format of the "add" command
Add trailing comma for the last element of a hash
Return a hash instead of a raw Groonga result by Groonga compatible commands.

Because raw results are hard to be handled by reducer/gatherer/collector.
Follow to the new response format of the Groonga commands
Test output format of Groonga commands correctly
Convert a Groonga generic response to a raw Groonga response
Add input and output adapter for CURD operations
Register CRUD input adapter correctly