Issue 315 - Text Stating that examples are not necessarily best practice

In order to address Issue 315, I agreed to propose some new text.

This is to be inserted in section 2 of the core either as a subsection entitled "Note on examples" or at the end  of an existing section.

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The examples which appear in this document are only intended to illustrate the correct syntax  of the features being specified. The examples are NOT intended to necessarily represent best  practice for implementing any particular security properties.

Specifically, the examples are constrained to contain only mechanisms defined in this  document. The only reason for this is to avoid requiring the reader to consult other documents  merely to understand the examples. It is NOT intended to suggest that the mechanisms  illustrated represent best practice or are the strongest available to implement the security  properties in question. In particular, mechanisms defined in other Token Profiles are known to  be stronger, more efficient and/or generally superior to some of the mechanisms shown in the  examples in this document.
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Hal