Global error messages (#261)

* Remove global error rendering

* Added basic Toasts

* Auto-close toasts

* 💚

* Flow fix, more reliable CI

frontend/components/Toasts/Toasts.js

@@ -0,0 +1,39 @@
+// @flow
+import React, { Component } from 'react';
+import { inject, observer } from 'mobx-react';
+import styled from 'styled-components';
+import { layout } from 'styles/constants';
+import Toast from './components/Toast';
+
+@observer class Toasts extends Component {
+  handleClose = index => {
+    this.props.errors.remove(index);
+  };
+
+  render() {
+    const { errors } = this.props;
+
+    return (
+      <List>
+        {errors.data.map((error, index) => (
+          <Toast
+            key={index}
+            onRequestClose={this.handleClose.bind(this, index)}
+            message={error}
+          />
+        ))}
+      </List>
+    );
+  }
+}
+
+const List = styled.ol`
+  position: fixed;
+  left: ${layout.hpadding};
+  bottom: ${layout.vpadding};
+  list-style: none;
+  margin: 0;
+  padding: 0;
+`;
+
+export default inject('errors')(Toasts);