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>

cfg/config_files.go

@@ -58,7 +58,7 @@ func CreateFile(fileName string) (string, error) {
 // Initialize takes care of settings up the initial state of WTF configuration
 // It ensures necessary directories and files exist
 func Initialize(hasCustom bool) {
-	if hasCustom == false {
+	if !hasCustom {
 		migrateOldConfig()
 	}
 
@@ -67,7 +67,7 @@ func Initialize(hasCustom bool) {
 	createXdgConfigDir()
 	createWtfConfigDir()
 
-	if hasCustom == false {
+	if !hasCustom {
 		createWtfConfigFile()
 		chmodConfigFile()
 	}

cfg/error_messages_test.go

@@ -1,14 +0,0 @@
-package cfg
-
-import (
-	"errors"
-)
-
-var (
-	errTest = errors.New("Busted")
-)
-
-func ExampleDisplayError() {
-	displayError(errTest)
-	// Output: Error: Busted
-}