provide livereload 'r' (restart option) to reload from root of app in CLI 3.x

CLI 3.x dropped the hot key command in terminal 'r' to perform the live reload from the root of the app (location.hash = ""). A live reload of the current page, resulting from a change to watched file, can leave the app in an consistent state thus requiring full reload. We need an option to restart the app at the root. I find the loss of this feature to be most problematic for Ionic v1 projects.

**Steps to Reproduce:**

1. ionic serve | ionic run --lc ios | or any other live reload command
2. navigate into your app so not at root page
3. touch a watched file
4. app reloads at current page (location.hash preserved)

**Output:**

CLI has no hot key 'r' to restart the from the root URL (location.hash=""). My work around is to type location.hash="" into the browser debugger.

Bumming.

**My `ionic info`:**

global packages:

@ionic/cli-plugin-proxy : 1.3.2
@ionic/cli-plugin-proxy : 1.3.2
@ionic/cli-utils : 1.5.0
Cordova CLI : 7.0.1
Gulp CLI : not installed globally
Ionic CLI : 3.5.0

local packages:

@ionic/cli-plugin-cordova : 1.4.1
@ionic/cli-plugin-gulp : 1.0.2
@ionic/cli-plugin-ionic1 : 2.0.1
Cordova Platforms : android 6.0.0 ios 4.4.0
Ionic Framework : ionic1 1.3.3

System:

Node : v7.4.0
OS : macOS Sierra
Xcode : Xcode 8.3.3 Build version 8E3004b
ios-deploy : 1.9.0
ios-sim : 5.0.13
npm : 4.1.1

**Other Information:**

先從 Ionic CLI 的 live-reload 命令及其終端熱鍵處理開始，然後透過離開根路由並修改一個受監視的檔案，使用 `ionic serve` 重現該行為。當 `r` 操作在清除 `location.hash` 的情況下重新載入應用程式，且現有的 live-reload 行為維持不變時，此變更就完成了。

由索引模型根據 Issue 內容生成。