Add fetch PR commits and display them in the activity stream

[elkuku]

This will fetch the commits for a PR and display them with the activity stream - as seen on GitHub.

This also tries to make our display more "GitHub like" and uses an octicon from #478

Example:

[brianteeman]

Looks good

This comment was created with the J!Tracker Application at http://issues.joomla.org/.

[b2z]

Testing. Have an error:

0 Exception
DateTimeZone::__construct(): Unknown or bad timezone (Z)

In: /vagrant/src/App/Tracker/Model/IssueModel.php@107
File    Line    Class->Method()
IssueModel.php  107 DateTimeZone->__construct()
Item.php    70  App\Tracker\Model\IssueModel->getItem()
Application.php 177 App\Tracker\Controller\Issue\Item->initialize()
AbstractWebApplication.php  121 JTracker\Application->doExecute()
index.php   35  Joomla\Application\AbstractWebApplication->execute()

[elkuku]

Seems that those things change with every PHP version :(

Please re-test.

[b2z]

Working :) I would move this styles <div class="span11" style="border: 1px solid silver; margin: 10px 0 10px;"> to the .css files and add border-radius: 3px;

[elkuku]

OK - I'm not the UI guy 👅

[b2z]

@mbabker note -> changes in DB