Adding v5.0 of SwiftMailer to composer.
Empty Email plugin and test committed.
Filled out the Plugin\Email::sendEmail(). Pulls in the following settings from the phpci config under the heading email_settings:

smtp_address
smtp_port
smtp_username
smtp_password

and

from_address
Adding Builder::getSystemConfig() to provide easy access to config.yml.
Fixing the email plugin so that it retrieves the system config correctly.
Adding email settings to the install command.
Updating the email plugin tests so that getSystemConfig is mocked correctly.
Adding Getter for builder's success property so that plugins can find out if the the build has succeeded or not.
Email plugin now looks in the yaml file for an addresses setting. All these addresses will be mailed with a pass or fail message.
css and html tweaks for plugin statueses in builds
Fix user entity not bein in registry
Fixes #75 user entity not being in the registry
Updating unit test to reflect that the test will fail without any addresses defined.
removed deprecated registry and use session
Adding a default address that is always mailed to by notifications.
Added basic body and title for the email notifications.
Update to composer.json to correct indentation.

swiftmailer was added automatically by PHPStorm and the indentation didn't match the rest of the file.
Merge pull request #79 from gabriel403/hotfix/75

Fixes #75 user entity not being in the registry
Adding patch to fix pagination, closes #73
ui tweaks