Allow volume above 100%

[schauveau]

The pulseaudio module limits the volume to 100% but in some cases it makes sense to raise the volume above 100%. The most common is when using a monitor or a laptop computer with a lousy speaker. Or that could simply be because you are listening to a bad audio stream.

The pulseaudio api has no practical limit (except for the 32 bit integer used to store the value) but it probably does not make sense to allow for very high volumes. Pavucontrol allows up to 150% which seems reasonable to me.

So I propose to add a configuration option max-volume.