Create cascade.php

Added PHP class for working with web services.

Function List:
```php
$obj = new Cascade($username, $password, $domain); //wrap in try/catch
$obj->changeAuth($username, $password); //wrap in try/catch
$identifier = $obj->identifier($type, $path, $siteName);
$identifier = $obj->identifierByPath($type, $path, $siteName);
$identifier = $obj->identifier($type, $id);
$identifier = $obj->identifierById($type, $id);
$acl= $obj->createACL($name, $level, $type);
$bool = $obj->result($reply);
$reply = $obj->listSites();
$reply = $obj->listSubscribers($identifier);
$reply = $obj->read($identifier);
$reply = $obj->readWorkflowSettings($identifier);
$reply = $obj->readAccessRights($identifier);
$reply = $obj->search($searchInfo);
$reply = $obj->edit($asset);
$reply = $obj->editWorkflowSettings($workflowSettings, $childrenInherit, $childrenRequire);
$reply = $obj->editAccessRights($acls, $children);
$reply = $obj->move($identifier, $destIdentifier, $newName, $doWorkflow = false);
$reply = $obj->create($asset);
$reply = $obj->copy($identifier, $destIdentifier, $newName);
$reply = $obj->delete($identifier);
$reply = $obj->publish($identifier, $destIdentifiers, $unpublish);

$array = $obj->objectToArray($object);
$object = $obj->arrayToObject($array);
$obj->test($arr);
```