Rake tasks now accept an options hash instead of only name, also tests

The original behaviour can be achieved through using.

TaskInQuestion.new(name: name_of_the_task)

The tests are fugly and aren't verbose (since the other tests in the suite do that)
Deprecation warning when using old RakeTask initialize format
RakeTasks::Doc, do not write to file if outfile is nil
nil rake_tasks output_file

This has been done to pass the travis ci tests until I smarter way of
creating these temporary files is found.
Merge pull request #181 from IceDragon200/rake_task_options

Rake Tasks accept options Hash