Add tests and fix vCard code.

Now, basic tests are almost ready.

TODO:
- importer test toward multiple vCard input (though it was tested with real usage)
- exporter tests for multiple composition
- tests with non-Ascii
- tests with special types like TYPE_DOCOMO

ISSUE:
In order to fully check the validity of exporter, we may have to develop
some vCard importer which rejects vCard which is valid but a kind of dubious.

Internal Issue Number: 2160039
9 files changed