BREAKING kill deprecated asset support

Summary:
This removes support for `require('image!…')`, which has been deprecated for a long time.

It is still possible to use images that are already bundled by the native app using the `nativeImageSource` module.
Check http://facebook.github.io/react-native/docs/images.html for detailed documentation.

Reviewed By: matryoshcow

Differential Revision: D4231208

fbshipit-source-id: 05ec4c1ca0fabdc3fbb652f8ad1acdf240a67955

local-cli/server/util/attachHMRServer.js

@@ -47,7 +47,7 @@ function attachHMRServer({httpServer, path, packagerServer}) {
       // `{path: '/a/b/c.js', deps: ['modA', 'modB', ...]}`
       return Promise.all(Object.values(response.dependencies).map(dep => {
         return dep.getName().then(depName => {
-          if (dep.isAsset() || dep.isAsset_DEPRECATED() || dep.isJSON()) {
+          if (dep.isAsset() || dep.isJSON()) {
             return Promise.resolve({path: dep.path, deps: []});
           }
           return packagerServer.getShallowDependencies({