pboling/sanitize_email — pull request #23 by rochers (2014-12-18 03:22:22+00:00)
Title: Eliminate prepended whitespace when neither prepend configurations are set to true

A bug was introduced where a single white space was being added to a subject line when neither of the prepend configurations were enabled.

This commit refactors the `prepend_custom_subject` method to add a space only when there are strings to prepend. It also introduces a new convenience method `custom_subject` which does the array join
previously done in `prepend_custom_subject`.

It also reduces the complexity of the method itself, which was introduced before to better handle messages with a `nil` subject.