res:dock:: use EntryManager
res:dock:: make preview window work(not finished)
res:dock:: preview window almost done.

TODO:
1. move between window.
2. close window.
3. multi-window.
res:dock:: preview window
Merge branch 'develop' into dock
res:dock:: preview window hover
res:dock:: make rightclick work
Merge branch 'develop' into dock
dock: add embed window support
app:dock:: fix typo
Merge branch 'develop' into dock
app/res:dock:: preview window works
res:dock:: clean code.
res:dock:: fix add/remove
res:dock:: try to merge activator and clientgroup to AppItem(not finished)
res/app:dock:: merge activator and clientgoup to item, applet window move animation
res:dock:: change the close icon
dock:clear preview content to prevent translucency window problem
app/res:dock:: update client window.

1. update client window.
2. forbidden _update_task_list on tasklist.c.
res:dock:: hide applet window when created