Overhauled the theme system

Also added a toggle switch :)

examples/switch/main.go

@@ -0,0 +1,25 @@
+package main
+
+import "git.tebibyte.media/sashakoshka/tomo"
+import "git.tebibyte.media/sashakoshka/tomo/layouts"
+import "git.tebibyte.media/sashakoshka/tomo/elements/basic"
+import _ "git.tebibyte.media/sashakoshka/tomo/backends/x"
+
+func main () {
+	tomo.Run(run)
+}
+
+func run () {
+	window, _ := tomo.NewWindow(2, 2)
+	window.SetTitle("Switches")
+
+	container := basic.NewContainer(layouts.Vertical { true, true })
+	window.Adopt(container)
+
+	container.Adopt(basic.NewSwitch("hahahah", false), false)
+	container.Adopt(basic.NewSwitch("hehehehheheh", false), false)
+	container.Adopt(basic.NewSwitch("you can flick da swicth", false), false)
+		
+	window.OnClose(tomo.Stop)
+	window.Show()
+}