Address InputTagHelper PR comments, add tests, and fix problems found

- remove `InputTagHelper.DefaultInputTypes`
- `InputTagHelper.Type` -> `InputTagHelper.InputTypeName`
- `GetFormat()` uses a `Dictionary` for data / time formats
 - also fix "decimal" handling
- move strings to `Resources`

nits:
- address TODO items to use `TagHelperOutputExtensions`
- pass `ModelMetadata` around

Author: dougbu

samples/TagHelperSample.Web/Views/Home/Create.cshtml

@@ -37,7 +37,7 @@
             <div class="col-md-10">
                 @* will automatically infer type="date" (reused HTML attribute) and format="{0:d}" (optional bound attribute) *@
                 <input for="DateOfBirth" />
-                <span validation-for="DateOfBirth">How old are you?</span>
+                <span validation-for="DateOfBirth">When were you born?</span>
             </div>
         </div>
         <div class="form-group">

samples/TagHelperSample.Web/Views/Home/Edit.cshtml

@@ -20,7 +20,7 @@
             <label for="DateOfBirth" class="control-label col-md-2" />
             <div class="col-md-10">
                 <input type="date" for="DateOfBirth" format="{0:d}" />
-                <span validation-for="DateOfBirth">How old are you?</span>
+                <span validation-for="DateOfBirth" />
             </div>
         </div>
         <div class="form-group">