Improve consistency, add examples.

Bugfixes and improvements in the types supported.

Add a few more options.

* Tags API
* Get attributes of an event as text
* Change threat level
* Feed generator
* Fix examples
* Bug fixes

Improvements, better compatibility with 2.4

New "add IP source" function

Improve error handling

Add unittests, fix typo.

Check the MISP instance to query is valid and improve consistency

Better error handling of no URL/Key are passed

Add support for downloading unzipped samples.