buflist: add mouse support

New options:
- buflist.look.mouse_jump_visited_buffer
- buflist.look.mouse_move_buffer
- buflist.look.mouse_wheel

New keys added by buflist plugin:
- @item(buflist):button1*      => hsignal:buflist_mouse
- @item(buflist):button2*      => hsignal:buflist_mouse
- @bar(buflist):ctrl-wheelup   => hsignal:buflist_mouse
- @bar(buflist):ctrl-wheeldown => hsignal:buflist_mouse

doc/en/autogen/user/buflist_options.adoc

@@ -74,6 +74,24 @@
 ** values: any string
 ** default value: `+"${buffer.hidden}==0"+`
 
+* [[option_buflist.look.mouse_jump_visited_buffer]] *buflist.look.mouse_jump_visited_buffer*
+** description: pass:none[if enabled, clicks with left/right buttons on the line with current buffer jump to previous/next visited buffer]
+** type: boolean
+** values: on, off
+** default value: `+off+`
+
+* [[option_buflist.look.mouse_move_buffer]] *buflist.look.mouse_move_buffer*
+** description: pass:none[if enabled, mouse gestures (drag & drop) move buffers in list]
+** type: boolean
+** values: on, off
+** default value: `+on+`
+
+* [[option_buflist.look.mouse_wheel]] *buflist.look.mouse_wheel*
+** description: pass:none[if enabled, mouse wheel up/down actions jump to previous/next buffer in list]
+** type: boolean
+** values: on, off
+** default value: `+on+`
+
 * [[option_buflist.look.signals_refresh]] *buflist.look.signals_refresh*
 ** description: pass:none[comma-separated list of signals that are hooked and trigger the refresh of buffers list]
 ** type: string

doc/en/weechat_dev.en.adoc

@@ -199,6 +199,7 @@ WeeChat "core" is located in following directories:
 |       buflist-bar-item.c          | Buflist bar items.
 |       buflist-command.c           | Buflist commands.
 |       buflist-config.c            | Buflist config options (file buflist.conf).
+|       buflist-mouse.c             | Buflist mouse actions.
 |    charset/                       | Charset plugin.
 |       charset.c                   | Charset functions.
 |    exec/                          | Exec plugin.