src/Tweeper.php: do not disable CURLOPT_SSL_VERIFYHOST and CURLOPT_SSL_VERIFYPEER

Do not disable CURLOPT_SSL_VERIFYHOST and CURLOPT_SSL_VERIFYPEER to
actually enforce certificate verification on TLS connections.

This was a relic of some early experimental code and should have not
made it to the stable release.

Moreover the value passed to CURLOPT_SSL_VERIFYHOST was also of the
wrong type, it should have been an integer rather than a boolean.