Update schema to follow DRAFT5+ spec

[koriym]

• Supports NAME element (missed)
• Supports REL element as an array (draft 5) #93
• Supports TITLE element (draft 5) #75 #78
• Supports DEF element (not defined yet but discussed)
• Split files for readability and future extension which enable us to have application-defined EXT schema.

You can try this schema in this empty alps document with JSON Schema auto-complete enable editor. (ex. IntelliJ IDE)

{
  "$schema": "http://raw.githubusercontent.com/koriym/spec/extended-schema/schemas/alps.json"
}