Fix style mistake made previously

* Fix style mistake in Central_hub.hpp
* Remove trailing spaces in makefile
Fix mistakes made in the dict branch

* Add uint32
* Fix segmentation faults
* Add operator<< overload
Call by copy in Listener and Filter

Instead of copying over Event_type*, copy over Event_type. Use
Event_type* instead of Event_type as template argument when using these
interfaces.

This change is useful because you can use a `Listener< std::shared_ptr<
Event_type > >` (or Filter) instead of `Listener< Event_type* >`
Add Listener to Hub adapter
Store raw instead of shared ptr in Draw_event
Add converters::Draw_event_to_dict
Add converters::Draw_event_to_dict dependencies to makefile
Add converters::Sfml_event_to_dict
Add converters::Sfml_event_to_dict dependencies to makefile
Send gui events in `std::shared_ptr`s
Merge branch 'converter'