Rake tasks

Add rake tasks as an easily importable ruby file
Do the rake tasks created with this library need to have these arguments passed in explicitly or is there some way to set them? For example, if I want to set `:log_level` do I need to do something like:

```
Beaker::Tasks::RakeTask.new("beaker:test:pe",:hosts,:log_level) do |t,args|
  t.type = 'pe'
  t.hosts = args[:hosts]
  t.log_level = args[:log_level]
end
```