UI Tweaks

• Move to big squares sidebar as suggested in T11153 (new color icons will be need)
• Move torrent queue from torrent toolbar into main view and add toolbar actions
• Hide many of the torrent columns by default
• Rearrange default torrent columns so that the most useful ones are shown first
• Hide many of the main toolbar actions by default
• Make start/pause toolbar buttons change dynamically
• Move plugins from view menu into preferences
• Center status bar text and hide by default