Move VM into a reducer

Otherwise it's very annoying to get access to the storage engine to load asset data.

src/lib/vm-listener-hoc.jsx

@@ -3,8 +3,6 @@ const PropTypes = require('prop-types');
 const React = require('react');
 const VM = require('scratch-vm');
 
-const Storage = require('./storage');
-
 const {connect} = require('react-redux');
 
 const targets = require('../reducers/targets');
@@ -92,13 +90,12 @@ const vmListenerHOC = function (WrappedComponent) {
         onTargetsUpdate: PropTypes.func,
         vm: PropTypes.instanceOf(VM).isRequired
     };
-    const defaultVM = new VM('vm-listener-hoc');
-    defaultVM.attachStorage(new Storage());
     VMListener.defaultProps = {
-        attachKeyboardEvents: true,
-        vm: defaultVM
+        attachKeyboardEvents: true
     };
-    const mapStateToProps = () => ({});
+    const mapStateToProps = state => ({
+        vm: state.vm
+    });
     const mapDispatchToProps = dispatch => ({
         onTargetsUpdate: data => {
             dispatch(targets.updateEditingTarget(data.editingTarget));

src/reducers/gui.js

@@ -2,6 +2,7 @@ const {combineReducers} = require('redux');
 
 module.exports = combineReducers({
     modals: require('./modals'),
+    monitors: require('./monitors'),
     targets: require('./targets'),
-    monitors: require('./monitors')
+    vm: require('./vm')
 });

src/reducers/vm.js

+const VM = require('scratch-vm');
+const Storage = require('../lib/storage');
+
+const SET_VM = 'scratch-gui/vm/SET_VM';
+const defaultVM = new VM();
+defaultVM.attachStorage(new Storage());
+const initialState = defaultVM;
+
+const reducer = function (state, action) {
+    if (typeof state === 'undefined') state = initialState;
+    switch (action.type) {
+    case SET_VM:
+        return action.vm;
+    default:
+        return state;
+    }
+};
+reducer.setVM = function (vm) {
+    return {
+        type: SET_VM,
+        vm: vm
+    };
+};
+module.exports = reducer;