title: OData substringof or startswith returning all items
body: <p>I'm trying to filter my results from a Rest Call.</p>
  
  <pre><code>$.ajax({
      type: "GET",
      headers: {
          "Accept": "application/json;odata=verbose"
      },
      dataType: "JSON",
      url: _spPageContextInfo.webServerRelativeUrl + "/_api/lists/getByTitle('Contacts')/items?$select=Title,Id&amp;$startswith('Title','" + request.term + "') eq true",
      success: function (data) {
      },
      error: function (ex) {
      }
  });
  </code></pre>
  
  <p>In my Contacts List i'm trying to retrieve the Title and the Id for Items which start with a String or which have the String somewhere in it, here for example it is the Name of somebody.</p>
  
  <p>I also tried it with substringof:</p>
  
  <pre><code>"/_api/lists/getByTitle('Contacts')/items?$select=Title,Id&amp;$substringof(" + request.term + ",'Title') eq true"
  </code></pre>
  
  <p>which delivers also the same result. </p>
  
  <p>It gives me all List Items from the List and no Filtering is applied.
  I build the Url for the Rest after looking here <a href="http://msdn.microsoft.com/en-us/library/fp142385.aspx#bk_determining">Programming using the SharePoint 2013 REST service</a>
  Like the Schema given there I think the Url looks ok, but it not seems so :)</p>
  
  <p><strong>Edit:</strong></p>
  
  <p>Applying the <code>$filter</code> like in the OData Uri Conventions gives me the following error:</p>
  
  <pre><code>{"error":{"code":"-1, Microsoft.SharePoint.SPException","message":{"lang":"en-US","value":"The query is not valid."}}}
  </code></pre>
  
  <p>Tried it with following Query Strings:</p>
  
  <pre><code>_api/lists/getByTitle('Contacts')/items?$select=Title,Id&amp;$filter=substringof(m,'Title') eq true
  
  _api/lists/getByTitle('Contacts')/items?$select=Title,Id&amp;$filter=substringof('m','Title') eq true
  
  _api/lists/getByTitle('Contacts')/items?$select=Title,Id&amp;$filter=substringof('m',Title) eq true
  </code></pre>