Warning class example

Hi group,

As per my action item from the last teleconference here you have more
examples of my Warning proposal.
Following with the example of the CSS validator, a failed validation
with warnings.

AFAIK a RDF property can't have multiple domains/ranges, so note that
"instance" has now been splitted in two new properties: "resultInstance"
(in TestResult class) and "warningInstance" (in Warning class)

<earl:TestResult rdf:ID="result">
  <earl:validity
rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#pass"/>
  <dc:title xml:lang="en">W3C CSS Validator Results</dc:title>
  <dc:description rdf:parseType="Literal" xml:lang="en">
    <div xmlns="http://www.w3.org/1999/xhtml">
      <p>This document is not valid CSS</p>
    </div>
  </dc:description>
  <earl:resultInstance rdf:resource"#instance1"
  <earl:warning rdf:resource="#warning1"/>
  <earl:warning rdf:resource="#warning2"/>
</earl:TestResult>

<earl:Warning rdf:ID="warning1">
  <dc:title xml:lang="en">Same color and background-color</dc:title>
  <dc:description rdf:parseType="Literal" xml:lang="en">
    <div xmlns="http://www.w3.org/1999/xhtml">
      <p>Same colors for color and background-color in two contexts</p>
    </div>
  </dc:description>
  <earl:warningInstance rdf:resource="#instance2"/>
</earl:Warning>

<earl:Warning rdf:ID="warning2">
  <dc:title xml:lang="en">No generic font family found</dc:title>
  <dc:description rdf:parseType="Literal" xml:lang="en">
    <div xmlns="http://www.w3.org/1999/xhtml">
      <p>You are encouraged to offer a generic family as a last
alternative</p>
    </div>
  </dc:description>
  <earl:warningInstance rdf:resource="#instance3"/>
  <earl:warningInstance rdf:resource="#instanceN"/>
</earl:Warning>

<earl:PointerCollection rdf:about="#instance1">
  <earl:LineCharLenPointer>
    <earl:line>55</earl:line>
    <earl:char>12</earl:char>
  </earl:LineCharLenPointer>
</earl:PointerCollection>

<earl:PointerCollection rdf:about="#instance2">
  <earl:LineCharLenPointer>
    <earl:line>145</earl:line>
    <earl:char>1</earl:char>
  </earl:LineCharLenPointer>
</earl:PointerCollection>

<earl:PointerCollection rdf:about="#instance3">
  <earl:LineCharLenPointer>
    <earl:line>154</earl:line>
    <earl:char>1</earl:char>
  </earl:LineCharLenPointer>
</earl:PointerCollection>

<earl:PointerCollection rdf:about="#instanceN">
  <earl:LineCharLenPointer>
    <earl:line>193</earl:line>
    <earl:char>1</earl:char>
  </earl:LineCharLenPointer>
</earl:PointerCollection>