Add Blob and File (#19)

Author: jasnell

index.bs

@@ -40,6 +40,7 @@ Interfaces:
 
 * {{AbortController}}
 * {{AbortSignal}}
+* {{Blob}}
 * {{ByteLengthQueuingStrategy}}
 * <code class="idl"><a data-link-type="idl" href="https://wicg.github.io/compression/#compression-stream">CompressionStream</a></code>
 * {{CountQueuingStrategy}}
@@ -49,6 +50,7 @@ Interfaces:
 * {{DOMException}}
 * {{Event}}
 * {{EventTarget}}
+* {{File}}
 * {{ReadableByteStreamController}}
 * {{ReadableStream}}
 * {{ReadableStreamBYOBReader}}