Only create a new struct to cwin, and move all to it.
Add PraghaDatabase and PraghaPreferences to PraghaLibraryPane and use it.
Port cur_library_view to PraghaPreferences renamed to library_syle.
Remove library_tree_nodes preferences!. Get it when change library-style.
Use library-style change signal to update library view.
Port sort_by_year and fuse_folders to PraghaPreferences
Separate update_style of raload.
Remove a lot of cwin replaced by cplaylist
Move a lot the code from gui.c to librarytree.c
Rename libraytree.c to pragha-library-pane.c and move a lot of code here.
Modularize a bit and move playlist_tree_export to pragha-library-pane
Move contexs menus to PraghaLibraryPane
Divide and conquer.. .
Move binding to fix library pane visibility when init.
Refresh tag completion based on PraghaDatabase changed signal.
Move pragha icon pixbuf to cwin..
Add another signal to PraghaDatabase to manage when change track db
Add a simple sidebar widget. 
Now only clean code. Not supports multiple panels.
Attach PraghaLibraryPane menu to PraghaSidebar.
Use sentitive of children widget as flag to show menu.
Directly hide the sidebar widget. Are binding.