read(): don't ignore frames if out is given?

[mgeier]

We already discussed this in #37 and the current behavior is this:

If both frames and out are specified in read(), the value of frames is silently ignored (same with dtype and always_2d).

While implementing the blocks() feature (#35), however, I found that it may be better to change this behavior slightly.

What about not ignoring frames?

That would mean if frames is smaller than the length of out, it is taken into account, if it is larger, it would still be ignored.
This would be similar to the default Python indexing behavior, where an index larger than the maximum index is silently truncated to the maximum index.

dtype and always_2d would still be ignored.

Is this a bad idea?

I didn't add tests to not interfere with the py.test rewrite, but we should add some test cases for this afterwards.

[bastibe]

I don't see any harm in this. Looks good.

By the way, you can see an up-to-date version of the (ongoing) test rewrite in the tests branch. Feel free to add your own. I am removing UnitTest based tests as I add test.py based ones.