Expose Joystick name and vendor

[capz]

When writing some joystick code, i noticed that every device provides it's own set of id's for buttons.
Exposing the vendor and name of the device would allow developers to configure any joystick they desire silently, instead of making the end-user select a configuration for it (or only supporting a single piece of joystick hardware).

[LaurentGomila]

That could be added, yes.

A sf::Joystick::Info structure providing a joystick's parameters could be written; button count and axes support could be moved there as well.

[NoobsArePeople2]

I've implemented this and posted about it on the forum here.

[Bromeon]

Implemented.