This enables package to inherit multiple parent packages.
Introduced new style package system.
- package and scenario informations are written as annotations
- package information file "package.yml" is replaced by "pione-package.json"
- scenario information file "scenario.yml" is replaced by "pione-scenario.json"
- add package database
- multiple package inheritance
Changed package annotation name "Edition" to "Editor".
Fixed a bug about spawning child task workers.
Updated Fib.pione.
Updated SerialProcessing example.
Fixed typos.