Listener orientation

[ac-stef]

Dropped in IRC from Quin.
Dumping it here, so it doesn't get lost...

Hey, this is Quin from Red Eclipse
Trying to find your versioning repository, but it doesn't seem obvious
Are you guys still using SVN or something?
I referenced AC's OpenAL implementation when implementing it in RE and I think I found a bug
Ah GitHub, nvm
OK, so this is incorrect, it results in the camera seeming to pan correctly, but it is actually upside down

AC/source/src/audiomanager.cpp

Line 677 in 13f0d8e

// listener

You can verify this by creating a sound source and standing in front of it and turning around
it will be louder when you're facing the wrong way
Also the up vector is supposed to be the camera's up direction, orthogonal to the camera direction
not just 0, 0, 1
Please feel free to reference my commit to RE and use the solution: redeclipse/base@b5dc84d
just make sure the cam matrix has been setup correctly before updating sounds
or calculate the vectors beforehand
Anyway, have a great day guys, my work here is done :)

thx :)