Net_SMTP, Auth_SASL, Net_Socket - Remove. Will use composer.

[totten]

Pre-requisite: civicrm/civicrm-core#7361

[totten]

• Net_Socket was a clean copy of 1.0.9.
• I couldn't tell authoritatively if we had patches on Auth_SASL, but there was nothing to suggest we did. (Nothing in VERSIONS or _ORIGINAL_)
• After CRM-14814 CRM-8744 breaks on SMTP svrs requiring secure authentication #66, Net_SMTP is better aligned with upstream, but there were a couple diffs:
  • The Auth_SASL calls used an older notation. This was necessary because Auth_SASL was out-of-date. But these PR's update both.
  • One of the error messages was modified with Civi-specific instructions ( https://github.com/civicrm/civicrm-packages/pull/135/files#diff-205d279ce3a50e2e2cfabaad983cac79L374 ). It seems like a decent idea to display more specific errors, but patching this file isn't a good way to do it. Better to patch civicrm-core to catch the error and report something better.

[seamuslee001]

@totten i think the only thing to do here is to clean up VERSIONS.php

[totten]

Replaced by #186