irc: add buffer for /list reply (closes #1972)

New options:

- irc.color.list_buffer_line_selected
- irc.color.list_buffer_line_selected_bg
- irc.look.list_buffer_sort
- irc.look.list_buffer_scroll_horizontal
- irc.look.new_list_position
- irc.look.list_buffer_topic_strip_colors

tests/unit/plugins/irc/test-irc-buffer.cpp

@@ -101,3 +101,13 @@ TEST(IrcBuffer, SearchPrivateLowestNumber)
 {
     /* TODO: write tests */
 }
+
+/*
+ * Tests functions:
+ *   irc_buffer_move_near_server
+ */
+
+TEST(IrcBuffer, IrcBufferMoveNearServer)
+{
+    /* TODO: write tests */
+}