Ensure consistent placement and delegation of descritions for presentations of primitive values

As found in the latest revision of [OData Core Part 3: CSDL, Version 4.0](https://www.oasis-open.org/committees/download.php/48835/odata-core-v4.0-wd01-part3-csdl-2013-04-12.doc) in section 3.5 Primitive Types, last paragraph:

"See [OData-ABNF] for the representation of primitive type values in URLs, and [OData-Atom] and [OData-JSON] for the representation in requests and responses."

These four components (tagged) need to be in sync with our decision what to describe exactly where.

Yesterday during the meeting we came to the conclusion, that all representation definitions shared across the formats (the intesection) shall be only described in ABNF, whilst differences among formats (or to conventional usage of the formats for OData) should be depicted in the respective format documents.

We might adjust this decision in the weeks to come, but in any case should ensure, the four components are clear and consistent along this dimension.