rc.lua: Use request::activate instead of client.focus.

For a long time, it was deemed overkill and made rc.lua less readable
without the documentation.

However it is now clear that it's handling of unfocusable clients and
general bypassing of both `awful.client.focus.filter` and
`awful.ewmh.activate` filters causes bugs. Fixing them individually
in each instance of `rc.lua` `client.focus = c` would add so much code
that all the clarity provided by not using request::activate would be
burried in boilerplate code.

Fix #2328

awesomerc.lua

@@ -155,16 +155,11 @@ local tasklist_buttons = gears.table.join(
                                               if c == client.focus then
                                                   c.minimized = true
                                               else
-                                                  -- Without this, the following
+                                                  c:emit_signal(
-                                                  -- :isvisible() makes no sense
+                                                      "request::activate",
-                                                  c.minimized = false
+                                                      "tasklist",
-                                                  if not c:isvisible() and c.first_tag then
+                                                      {raise = true}
-                                                      c.first_tag:view_only()
+                                                  )
-                                                  end
-                                                  -- This will also un-minimize
-                                                  -- the client, if needed
-                                                  client.focus = c
-                                                  c:raise()
                                               end
                                           end),
                      awful.button({ }, 3, client_menu_toggle_fn()),
@@ -335,8 +330,9 @@ globalkeys = gears.table.join(
                   local c = awful.client.restore()
                   -- Focus restored client
                   if c then
-                      client.focus = c
+                    c:emit_signal(
-                      c:raise()
+                        "request::activate", "key.unminimize", {raise = true}
+                    )
                   end
               end,
               {description = "restore minimized", group = "client"}),
@@ -459,17 +455,14 @@ end
 -- @DOC_CLIENT_BUTTONS@
 clientbuttons = gears.table.join(
     awful.button({ }, 1, function (c)
-        client.focus = c;
+        c:emit_signal("request::activate", "mouse_click", {raise = true})
-        c:raise()
     end),
     awful.button({ modkey }, 1, function (c)
-        client.focus = c
+        c:emit_signal("request::activate", "mouse_click", {raise = true})
-        c:raise()
         awful.mouse.client.move(c)
     end),
     awful.button({ modkey }, 3, function (c)
-        client.focus = c
+        c:emit_signal("request::activate", "mouse_click", {raise = true})
-        c:raise()
         awful.mouse.client.resize(c)
     end)
 )
@@ -559,13 +552,11 @@ client.connect_signal("request::titlebars", function(c)
     -- buttons for the titlebar
     local buttons = gears.table.join(
         awful.button({ }, 1, function()
-            client.focus = c
+            c:emit_signal("request::activate", "titlebar", {raise = true})
-            c:raise()
             awful.mouse.client.move(c)
         end),
         awful.button({ }, 3, function()
-            client.focus = c
+            c:emit_signal("request::activate", "titlebar", {raise = true})
-            c:raise()
             awful.mouse.client.resize(c)
         end)
     )
@@ -598,10 +589,7 @@ end)
 
 -- Enable sloppy focus, so that focus follows mouse.
 client.connect_signal("mouse::enter", function(c)
-    if awful.layout.get(c.screen) ~= awful.layout.suit.magnifier
+    c:emit_signal("request::activate", "mouse_enter", {raise = true})
-        and awful.client.focus.filter(c) then
-        client.focus = c
-    end
 end)
 
 -- @DOC_BORDER@