Add character identifiers to focusable widgets

When no widget has focus, press the letter key to focus on the widget
assigned to that letter.

Example:

    GitHub (d)

    Press "d" to focus on the GitHub widget.

git/display.go

@@ -15,8 +15,8 @@ func (widget *Widget) display() {
 		return
 	}
 
-	title := fmt.Sprintf("[green]%s[white]\n", repoData.Repository)
-	widget.View.SetTitle(fmt.Sprintf("%s- %s", widget.Name, title))
+	title := fmt.Sprintf("%s - [green]%s[white]", widget.Name, repoData.Repository)
+	widget.View.SetTitle(widget.ContextualTitle(title))
 
 	str := wtf.SigilStr(len(widget.Data), widget.Idx, widget.View) + "\n"
 	str = str + " [red]Branch[white]\n"

git/widget.go

@@ -34,7 +34,7 @@ type Widget struct {
 
 func NewWidget(app *tview.Application, pages *tview.Pages) *Widget {
 	widget := Widget{
-		TextWidget: wtf.NewTextWidget(" Git ", "git", true),
+		TextWidget: wtf.NewTextWidget("Git", "git", true),
 
 		app:   app,
 		Idx:   0,