Add ui state logging function

Now from the UI console, you can always call `logState()`, and it will print the state stringified into the console, ready to drop into the ui dev mode states folder, or other inspection.

This should make it easier to diagnose user bugs in the future.

ui/app/reducers.js

@@ -7,6 +7,8 @@ const reduceIdentities = require('./reducers/identities')
 const reduceMetamask = require('./reducers/metamask')
 const reduceApp = require('./reducers/app')
 
+window.METAMASK_CACHED_LOG_STATE = null
+
 module.exports = rootReducer
 
 function rootReducer (state, action) {
@@ -35,5 +37,11 @@ function rootReducer (state, action) {
 
   state.appState = reduceApp(state, action)
 
+  window.METAMASK_CACHED_LOG_STATE = state
   return state
 }
+
+window.logState = function() {
+  var stateString = JSON.stringify(window.METAMASK_CACHED_LOG_STATE, null, 2)
+  console.log(stateString)
+}