[#418,dr,!][s]: change DR schema strings to be like data locators (UR…

…L or relative path).

This eliminate the last usage of JSON pointer in the spec and simplifies life for implementors.

content/data-resource/contents.lr

@@ -260,7 +260,9 @@ A descriptor MAY contain any number of additional properties. Common properties
 
 A Data Resource MAY have a `schema` property to describe the schema of the resource data.
 
-The value for the `schema` property on a `resource` MUST be an `object` or a string that "references" an Object as detailed below.
+The value for the `schema` property on a `resource` MUST be an `object` representing the schema OR a `string` that identifies the location of the schema (i.e. the location specified MUST be a JSON document which is the schema).
+
+The restrictions on a `string` value are the same as those [defined above for the `path` data locator strings](#path-data-in-files) -- that is a fully qualified URL or a relative unix-style path.
 
 <div class="alert" markdown="block">
 NOTE: the Data Package specification places no restrictions on the form of this
@@ -270,17 +272,6 @@ Package][tdp] specification requires the schema value to conform to [Table
 Schema][jts].
 </div>
 
-## Schema References
-
-If `schema` is a string it is a "reference" to an Object and MUST be a URL. The URL MUST:
-
-* EITHER: resolve to a JSON document that is the schema
-* OR: include a fragment identifier which conforms to to [JSON
-  Pointer](http://tools.ietf.org/html/rfc6901) notation. The URL must then
-  resolve to a JSON document and the schema is obtained by resolving within
-  that JSON document using the fragment identifier as the JSON pointer as per
-  section 6 of the JSON pointer specification.  URL.
-
 [tdp]: /tabular-data-package/
 [jts]: /table-schema/
 [iana]: http://www.iana.org/assignments/character-sets/character-sets.xhtml