New feature

Now, thanks to Muggle, you can read a large file in chunks! Since a simple muggle cannot use magic, even less a powerful spell such as expelliarmus, he/she needs to read the file a little bit at time!
Muggle employs a generator method that allows to read nevents_per_chunk events at time from the file.

Now, it is possible also to easily change the order of the coordinates: by specifying a different dtype, one can change the order of timestamps, polarity and coordinates. This feature has still to be refined, though, bu the C code is perfectly capable of doing that.