Add options to enable/disable the LiveReload proxy, restrict access and to inject or not the livreload.js script tag

User can enable or disable the LiveReload Proxy server. When the proxy is enabled, workspace files can be access by using the http:// protocol instead of the file:// protocol Then, when the proxy is enable, users can choose to allow remote connections, which means that the files can be accessed by remote browsers or remote devices (such as smarphones or tablets) Also, when it is enabled, the proxy can modify on-the-fly the returned HTML pages by including a <script> tag which will load the livereload.js script without having to install a browser extension. This is especially interesting when the target browser runs on a device where extensions cannot be installed. By default, the proxy is disabled, which prevents access to the workspace file from remote devices and thus security breaches.