End of alpha: New features, improvement and fix update

With this update the alpha stage comes to an end and right after begins the beta stage with the same starting point as of this update.

To the users interested in continuing testing the following development versions please switch to the beta branch. The download link has been updated with the updated branch as well: https://github.com/ParticleCore/Iridium/wiki/Download

This version comes with three new features:

• Allow loudness normalization
• Memorize player size
• Memorize player volume

Improvement and bug fix details are included in the commit description.