Cleanup (#197)

* Removed unused code
* Use cclog for logging
* Wrap errors so that they can be unwrapped
* Revert wrong use of slices.Delete()
* Fix derivative values should be float
* Suggestions from the gocritic linter
* Fixed: interface method AddChannel must have all named params (inamedparam)
* Enable linter: errorlint
* Replace fmt.Sprintf("%d", i)) by strconv.Itoa(i) for improved performance
* Correct misspelled words
* Break up very long lines into multiple lines
* lp.NewMessage -> lp.NewMetric
* Preallocate slices of known length

collectors/memstatMetric.go

@@ -159,7 +159,7 @@ func (m *MemstatCollector) Init(config json.RawMessage) error {
 							file: f,
 							tags: map[string]string{
 								"type":    "memoryDomain",
-								"type-id": fmt.Sprintf("%d", id),
+								"type-id": strconv.Itoa(id),
 							},
 						}
 						m.nodefiles[id] = f