20191215 code improvements (#790)

* Upgrade godo to latest
* Fix a bunch of issues found by
* Running staticcheck on a codebase for the first time is a sobering experience
* go mod tidy
* More static improvements

Signed-off-by: Chris Cummer <chriscummer@me.com>

modules/bargraph/widget.go

@@ -12,11 +12,6 @@ import (
 	"github.com/wtfutil/wtf/view"
 )
 
-var (
-	ok      = true
-	started = false
-)
-
 // Widget define wtf widget to register widget later
 type Widget struct {
 	view.BarGraph