Granatier has now optional dependency for OpenAL and SndFile

[Mathias Kraus]

Hi together,

Just for information.
I just committed a change to Granatier to use TagaroAudio as optional sound 
backend, if OpenAL and SndFile is found.

https://projects.kde.org/projects/playground/games/libtagaro

The necessary files from Tagaro are copied to the Granatier sources until 
there is a Tagaro release.
With TagaroAudio, there is no need for the optional Gluon dependency, so I 
removed it.

Regards,
Mathias Kraus