Make all examples in vibe.data.serialization into unit tests and work around DDOC JSON output issues.

The "endline" entry for unit tests points to the first line of the next declaration instead of the last line of the current declaration. Putting the opening "{" on a new line allows DDOX to find the end of the unit test block by searching backwards for "}".
Remove old documentation generation scripts (now done using "dub build --build=ddox").