Passing options to call_task() doesn't work for distutils tasks when using long task names

According to [the documentation](http://pythonhosted.org//Paver/pavement.html#more-complex-dependencies), it should be possible to pass options to a task executed via call_task() like this:

```python
@task
def greet_user(options):
    call_task('say_hello', options={
        'long_username' : 'Kitty'
    })
```

Attached is a minimal test case (`example_project-0.1.tar.gz`) in which I try to do just that, except I'm using the task's long name:

**example_project-0.1/pavement.py**:
```python
@task
def some_task_that_calls_sdist(options):
    call_task("distutils.command.sdist", options = { "keep_temp": True })
    # ...
```

This code is followed by an assertion that checks whether the temporary folder used by `sdist` has been preserved, as should be the case because I used the `keep_temp` option.

When I run `paver some_task_that_calls_sdist` using the latest github version of Paver, the option is never passed on to sdist, however, and the temporary folder deleted as usual.

I debugged this for a bit and what happens is this:
* [`call_task` saves the passed options under **the name that was used when calling the task**](https://github.com/paver/paver/blob/master/paver/tasks.py#L147)
* [`DistutilsTask.__call__` fetches the options by the task's **short name**](https://github.com/paver/paver/blob/master/paver/setuputils.py#L165)

Of course, this doesn't work in my case because the short name (`sdist`) isn't equal to the name I called the task with (`distutils.command.sdist`).

I have thus attached a patch that attempts to fix this by ...
* "normalising" the task name before saving options; always use the task's "internal" long name, i.e. `Task.name`.
* pulling in the options saved for the short *and* long task name in `DistutilsTask.__call__`. Not sure whether we need the short-name-options at all.

Note that normalisation is also necessary because `sdist` can be referred to as `distutils.command.sdist`, like I do in the example `pavement.py`, but its internal name will be `setuptools.command.sdist`. So doing just the second thing won't work, you also always have to normalise.

This is just a proposal for a fix, but IMO you should change the rest of the code to normalise task names as well, unless you have a better idea.

## Attachments ##

* Test case: [example_project-0.1.tar.gz](http://sol.fr.am/res/paver_bugs/example_project-0.1.tar.gz)
* Patch: [long_task_name_and_options.patch](http://sol.fr.am/res/paver_bugs/long_task_name_and_options.patch)