Changes for version 2.04
- fixed a document typo pointed by kawasaki@annocpan
- make DATA handle closed for error mssages in support_by_pp mode.
- switched JSON::Backend::XS::Supportable wrapper de/encode to changing symbolic tables for croak messages and speed.
- fixed support_by_pp setting
- [JSON::PP] 2.04
- enhanced the error message compatiblity to XS.