This makes it possible to encode using a target quality instead of
target bitrate and also makes min and max bitrates optionals.
This fixes bug #3092367.
A lame path option has been added when using MP3 compression. For CLI it can be set using -lame-path. In the GUI it can be set in the advanced MP3 options page. There is also a check on lame in the GUI tools now.
svn-id: r48610