Latest changes on the chunked dot examples.

This is just a pull request of the samples of chunked dot. This was done in order to make all the different implementations to look similar so that a clear pattern is made evident.

I think it is a good idea to have all this in master before code starts moving to the cleaned up repo.

Note that there are only changes on files under samples/ directory.

Apart from that:
 - I added .blz files to the gitignore.
 - I removed test_iterators.py at the root of the repo, checking at history it seems that at some point I added it by error.