Support for bulk operations

[dardoguidobono]

Support for bulk operations see pr ( work in progress )
Thnks.

Example call:

`<?php
$subscribers = [
[
'email' => 'dardoguidobono+1@gmail.com',
'confirmed' => 1,
'htmlemail' => 1,
'password' => '',
'disabled' => 0,
'foreignkey' => '',
'subscribepage' => 0,
],
[
'email' => 'dardoguidobono+2@gmail.com',
'confirmed' => 1,
'htmlemail' => 1,
'password' => '',
'disabled' => 0,
'foreignkey' => '',
'subscribepage' => 0,
]

];
$url = 'http://xxxx/lists/admin/?page=call&pi=restapi';

//initialize cUrl for remote content
$c = curl_init();
curl_setopt( $c, CURLOPT_COOKIEFILE, 'phpList_RESTAPI_Helper' );
curl_setopt( $c, CURLOPT_COOKIEJAR, 'phpList_RESTAPI_Helper' );
curl_setopt( $c, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt( $c, CURLOPT_POST, 1 );

//Call for the session-id via /login
curl_setopt( $c, CURLOPT_URL, $url );
curl_setopt( $c, CURLOPT_POSTFIELDS, 'cmd=login&login=admin&password=xxxx' );
$result = curl_exec( $c );
$result = json_decode( $result );
//Get all lists in phpList via /listsGet
curl_setopt( $c, CURLOPT_URL, $url );
curl_setopt( $c, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt( $c, CURLOPT_POST, 1 );
curl_setopt( $c, CURLOPT_POSTFIELDS, "cmd=subscriberBulkAdd&subscribers=".urlencode(json_encode($subscribers)) );
$result = curl_exec( $c );
$result = json_decode( $result );

//Now close the cUrl when finished
curl_close( $c );

//Dump all lists in phpList via /listsGet
var_dump( $result->data );`