Sounds

[nurupo]

Add support of sounds, nicely donated by Adam Reid #7

Ideally there should be a SoundManager singleton class, which would get path to where music is stored from Settings class and would be called from all around the code like

SoundManager::getInstance().play(Sound::FriendRequestReceived);

Note that some sounds should be looped until requested to stop.

A settings page should be implemented for configuring sounds. Enable/disable all or partially some sounds. There is no need in adding volume control, since it can be tweaked per application in modern operating systems.

Support of sounds packs would be a plus.
(What should happen when you have a looping sound playing and you switch the sound pack?)