Code Migration

- Migrated taskd JSON parser into task, to provide encode/decode
  capability to Task::composeJSON.
- Migrated taskd utf8 code, replacing old unused code.
- Added unit tests or JSON.
- Migrated Tree updates from taskd.

test/.gitignore

@@ -11,6 +11,7 @@ duration.t
 file.t
 filt.t
 grid.t
+json.t
 lisp.t
 list.t
 nibbler.t