Updated Termdash API (markdown)

Termdash-API.md

@@ -24,26 +24,60 @@ The public API surface of this package consists of the following:
 
 The **Run** function provides the simplest way to run a Termdash based application. Run blocks until the provided context expires, therefore we need a trigger to close the context, e.g. a keyboard shortcut or a timeout. When Termdash is started using this function, the screen is redrawn periodically.
 
-The following code snippet starts Termdash with an empty container and no widgets. Termdash will quit after 5 seconds when the context expires.
+The following code snippet starts Termdash with an empty container and no widgets. Termdash will quit after five seconds when the context expires.
 
 ```go
 // Create the terminal.
 t, err := termbox.New()
 if err != nil {
-    fmt.Errorf("termbox.New => %v", err)
+    return fmt.Errorf("termbox.New => %v", err)
 }
 defer t.Close()
 
 // Create the container without widgets.
 c, err := container.New(t)
 if err != nil {
-    fmt.Errorf("termbox.New => %v", err)
+    return fmt.Errorf("container.New => %v", err)
 }
 
 // Termdash runs until the context expires.
 ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 defer cancel()
-if err := Run(ctx, t, c); err != nil {
-    panic(err)
+if err := termdash.Run(ctx, t, c); err != nil {
+    return fmt.Errorf("termdash.Run => %v", err)
+}
+```
+
+## [termdash.NewController](https://github.com/mum4k/termdash/blob/ffbf88caeddb1735dcf2a5f735eec80dc9cf9fe7/termdash.go#L113-L130):
+
+The **NewController** function creates a new **Controller** instance which allows the user to manually trigger a screen redraw. Periodic redraws are disabled in this mode. Termdash will still redraw the screen each time an input event happens, e.g. a keyboard, a mouse event or a terminal resize.
+
+The following code snippet starts Termdash with an empty container and no widgets and redraws the screen once. As opposed to **Run**, the following code isn't blocking so the user remains in control of the main goroutine.
+
+```go
+// Create the terminal.
+t, err := termbox.New()
+if err != nil {
+    return fmt.Errorf("termbox.New => %v", err)
+}
+defer t.Close()
+
+// Create the container without widgets.
+c, err := container.New(t)
+if err != nil {
+    return fmt.Errorf("container.New => %v", err)
+}
+
+// Create the controller.
+ctrl, err := termdash.NewController(t, c)
+if err != nil {
+    return fmt.Errorf("termdash.NewController => %v", err)
+}
+// Close the controller and termdash once it isn't required anymore.
+defer ctrl.Close()
+
+// Redraw the screen manually.
+if err := ctrl.Redraw(); err != nil {
+    return fmt.Errorf("ctrl.Redraw => %v", err)
 }
 ```