Preliminary implementation of border-less mode

Not yet functional but most ingredients are there

data/core/titleview.lua

@@ -0,0 +1,30 @@
+local core = require "core"
+local style = require "core.style"
+local StatusView = require "core.statusview"
+
+
+local TitleView = StatusView:extend()
+
+TitleView.separator = " "
+
+function TitleView:new()
+  TitleView.super.new(self)
+end
+
+
+function TitleView:on_mouse_pressed()
+  core.set_active_view(core.last_active_view)
+end
+
+
+function TitleView:get_items()
+  local title = core.compose_window_title(core.window_title)
+  return {
+    style.text, style.icon_font, "g ", style.font, title,
+  }, {
+    style.text, style.icon_font, "_", TitleView.separator, "w", TitleView.separator, "W",
+  }
+end
+
+
+return TitleView