Add Task::listContents and Task::fileExists
Add ability to pass just a Task to fireTasksQueue
Add ability to pass base class of Rocketeer Tasks to Task::executeTask
Add basic deploy:check command, make deploy:setup use it beforehand
Move the logic behind Task::executeTask to TasksQueue::buildTask
Make Task::runComposer take into account a local `composer.phar`
Add Task helper to run outstanding migrations
Update README