Introduced WNumberDb, to display numeric volume and gain. Allow string substitution by %1 in WNumber.
added ratio2db() and db2ratio()
removed unused function
inherid WNumberDb from WNumber
Removed ConstFactor from WNumber. It was badly named, unused and undocumented.
We can acheve the same function by using Transform inside the connection.
Merge pull request #245 from daschuer/wnumberdb

WNumberDb a dB Display