title: Bleve is not indexing the numeric and date appropriately
body: <p>Search request on the bleve returns the response where string fields are exact but numeric and date fields are not returning as expacted </p>
  
  <pre><code>{
  "back_image": "",
  "cover_image": "\\storage\\8\\c9e6325b-8cd8-402b-9e37-54b7119a5c22.png",
  "created_at": " \u0001\u0014s\u0002\u000b\r\u001b_,\u0000",
  "id": " \u0001@\u001f\u0000\u0000\u0000\u0000\u0000\u0000\u0000",
  "score": 0.02789571168954376,
  "status": " \u0001\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000",
  "tags": "i ",
  "time": 1004300,
  "title": "MyArtu",
  "total": 1,
  "type": " \u0001?x\u0000\u0000\u0000\u0000\u0000\u0000\u0000",
  "updated_at": " \u0001\u0014t\u001f^\u0010,\u0004T\u0000",
  "user_id": " \u0001@\u0010\u0000\u0000\u0000\u0000\u0000\u0000\u0000",
  "visibility": " \u0001\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000"}
  </code></pre>
  
  <p>Bleve is not working with the numeric values and date for me.</p>
  
  <p>My Mapping Code is</p>
  
  <pre><code>    publication := bleve.NewDocumentMapping()
  
      publicationCoverImage := bleve.NewTextFieldMapping()
      publicationCoverImage.Store = true
      publication.AddFieldMappingsAt("cover_image",publicationCoverImage)
  
      publicationId := bleve.NewNumericFieldMapping()
      publicationId.Store = true
      publication.AddFieldMappingsAt("id", publicationId)
  
      publicationTags := bleve.NewTextFieldMapping()
      publicationTags.Store = true
      publication.AddFieldMappingsAt("tags", publicationTags)
  
      publicationTitle := bleve.NewTextFieldMapping()
      publicationTitle.Store = true
      publication.AddFieldMappingsAt("title", publicationTitle)
  
      mapping := bleve.NewIndexMapping()
      mapping.AddDocumentMapping("publication",publication)
      PublicationIndex, PublicationErr = bleve.New("publications.bleve", mapping)
  </code></pre>
  
  <p>Here is the code that is reponsible generating the output </p>
  
  <pre><code>for _,hit := range result.Hits {
          doc, _ := search.PublicationIndex.Document(hit.ID)
          for _, field := range doc.Fields {
              resp[string(filed.Name())] = fmt.Sprint(string(filed.Value()))
          }           
      }
  </code></pre>