Remove aerc specific code from the ui

Separatiing the ui code from aerc makes it usable as a library in
other projects.

aerc.go

@@ -150,12 +150,16 @@ func main() {
 		return getCompletions(aerc, cmd)
 	}, &commands.CmdHistory)
 
-	ui, err = libui.Initialize(conf, aerc)
+	ui, err = libui.Initialize(aerc)
 	if err != nil {
 		panic(err)
 	}
 	defer ui.Close()
 
+	if conf.Ui.MouseEnabled {
+		ui.EnableMouse()
+	}
+
 	logger.Println("Starting Unix server")
 	as, err := lib.StartServer(logger)
 	if err != nil {

lib/ui/ui.go

@@ -4,8 +4,6 @@ import (
 	"sync/atomic"
 
 	"github.com/gdamore/tcell"
-
-	"git.sr.ht/~sircmpwn/aerc/config"
 )
 
 type UI struct {
@@ -18,8 +16,7 @@ type UI struct {
 	invalid  int32 // access via atomic
 }
 
-func Initialize(conf *config.AercConfig,
-	content DrawableInteractiveBeeper) (*UI, error) {
+func Initialize(content DrawableInteractiveBeeper) (*UI, error) {
 
 	screen, err := tcell.NewScreen()
 	if err != nil {
@@ -32,9 +29,6 @@ func Initialize(conf *config.AercConfig,
 
 	screen.Clear()
 	screen.HideCursor()
-	if conf.Ui.MouseEnabled {
-		screen.EnableMouse()
-	}
 
 	width, height := screen.Size()
 
@@ -101,3 +95,7 @@ func (state *UI) Tick() bool {
 
 	return more
 }
+
+func (state *UI) EnableMouse() {
+	state.screen.EnableMouse()
+}