Fixed descriptor type

[NaokiTsuchiya]

Current json schema for descriptor is wrong.

ex.

• https://github.com/koriym/app-state-diagram/blob/master/docs/blog/profile.json
• https://github.com/koriym/app-state-diagram/blob/master/docs/todomvc/profile.json

Fixed descriptor type to array from object.

It is used the following profiles and verified by IDE.

• https://github.com/NaokiTsuchiya/app-state-diagram/blob/fix-example-schema/docs/blog/profile.json
• https://github.com/NaokiTsuchiya/app-state-diagram/blob/fix-example-schema/docs/todomvc/profile.json
• https://github.com/NaokiTsuchiya/LonelyState/blob/master/profile.json

[koriym]

LGTM