PrefBar 4.3

Cleaned up configuration dialog (Manuel Reimer):
 buttons between lists dropped
 context menu added
 items can be edited via doubleclick
 items may be moved between/in lists via drag&drop

Added several smaller fixes for SeaMonkey 2.0 (Manuel Reimer)

Separated the plugin toggle stuff to two simple functions, as newer Firefox releases will require me to also use this code to toggle Java (Manuel Reimer)

Changelog 4.3

norah'#さんの日本語バージョン 4.1.2 から4.2→4.3と英語版を上書きして使ってるけど大丈夫なのかしら? (;^_^A