added type and title properties to Link class

simple proposal for change to allow type and title properties to Link class,
of course, on board with any alternate which allows for same end result.
the following example set values for new 'title' property of Link:

```json
[ {
  "links" : [ {
    "rel" : "self",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/widgets/1"
  } ],
  "name" : "widget-0",
  "whatsitLinks" : [ {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/1",
    "title" : "whatsit-0-0"
  }, {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/2",
    "title" : "whatsit-0-1"
  } ]
}, {
  "links" : [ {
    "rel" : "self",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/widgets/2"
  } ],
  "name" : "widget-1",
  "whatsitLinks" : [ {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/3",
    "title" : "whatsit-1-0"
  }, {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/4",
    "title" : "whatsit-1-1"
  } ]
}, {
  "links" : [ {
    "rel" : "self",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/widgets/3"
  } ],
  "name" : "widget-2",
  "whatsitLinks" : [ {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/5",
    "title" : "whatsit-2-0"
  }, {
    "rel" : "whatsit",
    "href" : "http://localhost:8080/acme-widget-hateoas-web-api/whatsits/6",
    "title" : "whatsit-2-1"
  } ]
} ]
```