[classify] Have correct argument count to logging.
[sink-input-ext] Set volume factor in SINK_INPUT_FIXATE.

Previously volume factor was set in SINK_INPUT_PUT and at that time
sink-input was already attached to sink's IO-thread. This means some
data was already passed when the volume factor was applied.
As a fix add volume factor a bit earlier, in
PA_CORE_HOOK_SINK_INPUT_FIXATE.
[policy] Fix const in various places.

Const was casted away from constant strings in multiple places. Also
some places used char* when the string wouldn't be or shouldn't be
changed in the function. Add const to these places and modify functions
so that constant strings are returned as const.
Merge pull request #10 from jusa/dev

Set volume factor in SINK_INPUT_FIXATE.