Drop ncurses dependency

Close #818

src/tui/ncurses.go

@@ -1,3 +1,4 @@
+// +build ncurses
 // +build !windows
 // +build !tcell
 
@@ -32,6 +33,10 @@ import (
 	"unicode/utf8"
 )
 
+func HasFullscreenRenderer() bool {
+	return true
+}
+
 type Attr C.uint
 
 type CursesWindow struct {