tizen-volume-api: Use pa_balance_valid()
tizen-volume-api: Better rounding in bvolume_snprint_balance()
tizen-volume-api: Remove redundant parentheses
volume: Increase PA_SW_VOLUME_SNPRINT_DB_MAX

10 bytes isn't enough for "-123.45 dB", including the terminating null
byte.
pactl: Fix relative adjustment with set-volume-control-volume

volume_relative_adjust() used the global volume variable, which didn't
work in case of set-volume-control-volume, because that command saves
the user-specified volume in the bvolume variable instead of the
volume variable. Now volume_relative_adjust() takes the adjustment as
a parameter instead of using the global variable, so we can now use
the correct variable depending on the context.

This also fixes set-volume-control-volume with non-relative volumes.
The global volume variable was being used also in that case, even
though the volume is actually stored in bvolume.
pactl: Check if the user gives too many balance channels
tizen-volume-api: Add some more bvolume helpers
tizen-volume-api: Add stub implementation of pa_tizen_volume_api

pa_tizen_volume_api is a singleton object that will keep track of all
volume control objects in the system (and any other objects that will
be needed in the Tizen volume API) and provide a hook interface for
getting change notifications.
tizen-volume-api: Connect to pa_tizen_volume_api from module-tizen-volume-api
tizen-volume-api: Introduce pa_volume_control
tizen-volume-api: Implement getting volume control info
tizen-volume-api: Send subscription events for new and removed volume controls
volume-control: Add support for setting volume
tizen-volume-api: Allow clients to set volume control volume
tizen-volume-api: Send subscription events when volume control volume changes