Replace guzzle with httplug

[veewee]

fixes #25

[veewee]

Upgrading:

composer require psr/http-message:^1.0 php-http/httplug:^1.1 php-http/message-factory:^1.0 php-http/discovery:^1.3 php-http/message:^1.6 php-http/client-common:^1.6 php-http/guzzle6-adapter:^1.1

// Wrap your guzzle client in a HTTPlug adapter:
$httpClient = new Client($guzzleClient);

// Use the new HttPlugHandle instead of the old GuzzleHandle
$clientBuilder->withHandler(HttPlugHandle::createForClient($httpClient));

// use the new HttPlugWsdlProvider instead of the old GuzzleWsdlHandle
$clientBuilder->withWsdlProvider(HttPlugWsdlProvider::createForClient($httpClient));

// If you are using NTLM:
// Remove the NtlmMiddleware and add the curl options to the guzzle client configuration instead:
$httpClient = Client::createWithConfig(['curl' => [
    CURLOPT_HTTPAUTH => CURLAUTH_NTLM,
    CURLOPT_USERPWD => 'username:password',
]]);