rejig the structure of the plugin, remove the toolbar and replace with a...

... menu and recoded to make the plugin both RB2.9x and RB3.0+ compatible

Hi,

  I've had a quick hack at the code and plugin structure to make the plugin work in both a system wide location and locally.

At the same time I've made the plugin both RB2.96-2.99 compatible as well as RB3.0+ compatible.

Note - I've used a bash script to-do the install - not the setup.py - if you dont want this script, feel free to delete etc.  Heck - if you dont like any of the changes, I dont mind if you disregard the pull request.

for RB2.96 - RB2.99

    ./install.sh

for RB3.0+

    ./install.sh --rb3

I've used my rb3compat module that I developed for many of my plugins - and which is also used by many other plugin authors.  This gives a plugin the flexibility for all RB versions.

Note - the only issue is that you cannot have toolbar buttons to invoke the functionality - in RB2.99 and later, the rhythmbox maintainer took away that option.  You must use a menu option to invoke the functionality.  

Note 2 - the preference options I saw only did their stuff when rhythmbox is restarted.  You might want to add a label to the plugin dialog to say "please restart rhythmbox".  Better still would be to actually do something when the options are clicked.