Replace sprockets/browserify with Webpack (#2617)

* Replace browserify with webpack

* Add react-intl-translations-manager

* Do not minify in development, add offline-plugin for ServiceWorker background cache updates

* Adjust tests and dependencies

* Fix production deployments

* Fix tests

* More optimizations

* Improve travis cache for npm stuff

* Re-run travis

* Add back support for custom.scss as before

* Remove offline-plugin and babili

* Fix issue with Immutable.List().unshift(...values) not working as expected

* Make travis load schema instead of running all migrations in sequence

* Fix missing React import in WarningContainer. Optimize rendering performance by using ImmutablePureComponent instead of
React.PureComponent. ImmutablePureComponent uses Immutable.is() to compare props. Replace dynamic callback bindings in
<UI />

* Add react definitions to places that use JSX

* Add Procfile.dev for running rails, webpack and streaming API at the same time

app/javascript/mastodon/actions/cards.js

@@ -0,0 +1,52 @@
+import api from '../api';
+
+export const STATUS_CARD_FETCH_REQUEST = 'STATUS_CARD_FETCH_REQUEST';
+export const STATUS_CARD_FETCH_SUCCESS = 'STATUS_CARD_FETCH_SUCCESS';
+export const STATUS_CARD_FETCH_FAIL    = 'STATUS_CARD_FETCH_FAIL';
+
+export function fetchStatusCard(id) {
+  return (dispatch, getState) => {
+    if (getState().getIn(['cards', id], null) !== null) {
+      return;
+    }
+
+    dispatch(fetchStatusCardRequest(id));
+
+    api(getState).get(`/api/v1/statuses/${id}/card`).then(response => {
+      if (!response.data.url) {
+        return;
+      }
+
+      dispatch(fetchStatusCardSuccess(id, response.data));
+    }).catch(error => {
+      dispatch(fetchStatusCardFail(id, error));
+    });
+  };
+};
+
+export function fetchStatusCardRequest(id) {
+  return {
+    type: STATUS_CARD_FETCH_REQUEST,
+    id,
+    skipLoading: true
+  };
+};
+
+export function fetchStatusCardSuccess(id, card) {
+  return {
+    type: STATUS_CARD_FETCH_SUCCESS,
+    id,
+    card,
+    skipLoading: true
+  };
+};
+
+export function fetchStatusCardFail(id, error) {
+  return {
+    type: STATUS_CARD_FETCH_FAIL,
+    id,
+    error,
+    skipLoading: true,
+    skipAlert: true
+  };
+};