Improve sent message detection for sent message tagging

Fixed: Cannot tag a composed message when "Place replies in the folder of the message being repiled to" is checked in a "Copies & Folders" option

Fixed: a tag toolbar will be hidden when Lightning 0.8 is installed
Fixed: zh-CN strings is not translated fully
Added: tags can be sorted by alphabetical order in the Category Editor
Fixed: a setting for hiding access keys is not saved
Fixed: tagging does not work if you open a messeger compose window from address book window
Fixed: an error message is appear when a message is saved by a message compose window

Added: add a new toolbar automatically when a tag toolbar overflows (set maximum number of toolbars before you use this functionality)
Added: a button/menu to add/remove all tags in a category
Added: the category editor shows a query of a saved search category
Added: a tooltip of a saved search category shows a query of it
Fixed: the category editor is too narrow in some languages
Fixed: some icons are missing in some themes
Fixed: unnecessary updates of a tag toolbar on startup of Thunderbird

Added: include de-DE locale

Added: Tag search functionalities
* Search tags on Tag Bar
* Search can be saved as a category like a saved search folder
* Search and select tags on Category Editor
Added: Remember the last selected category in a folder
Added: Add tag toolbar to the message compose window
* Specified tags are add to the message saved in the sent folder
Added: Add "Remove All Tags" toolbar button
Fixed: Display settings will be changed when you cancel toolbar customization

Fixed: tag toolbar collapsing was not persisted
Added: update locales

Fixed: Cannot create new category if no category is existed

Fixed: tag toolbar is not updated when new window is opened