Update PHPMailer to 5.2.10 from 5.2.7.

Includes two modifications for WordPress:
* Removes support for NTLM in `class-smtp.php` since the required client (`extras/ntlm_sasl_client.php`) is not distributed as part of WordPress.
* Requires `class-smtp.php` for backwards compatibility with direct (non-wp_mail()) uses of PHPMailer, as the autoloader isn't used. See [27385].

This also includes a change to our `MockMailer` for unit tests. It now overrides `postSend() instead of `send()`, and `preSend()`.
`preSend()` resets `$this->Encoding` because PHPMailer doesn't clean up after itself / presets all variables. This becomes an issue when `PHPMailer::createBody()` sets `$this->Encoding = 'quoted-printable'` (away from it's default of 8bit) when it encounters a line longer than 998 characters. `Tests_Comment::test_comment_field_lengths` is such a case.

props MattyRob, dd32.
fixes #28909.
Built from https://develop.svn.wordpress.org/trunk@33124


git-svn-id: http://core.svn.wordpress.org/trunk@33095 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-beta1-33123';
+$wp_version = '4.3-beta1-33124';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.