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

internal/metricRouter/metricCache.go

@@ -137,12 +137,12 @@ func (c *metricCache) Add(metric lp.CCMessage) {
 		p := c.intervals[c.curPeriod]
 		if p.numMetrics < p.sizeMetrics {
 			p.metrics[p.numMetrics] = metric
-			p.numMetrics = p.numMetrics + 1
+			p.numMetrics++
 			p.stopstamp = metric.Time()
 		} else {
 			p.metrics = append(p.metrics, metric)
-			p.numMetrics = p.numMetrics + 1
-			p.sizeMetrics = p.sizeMetrics + 1
+			p.numMetrics++
+			p.sizeMetrics++
 			p.stopstamp = metric.Time()
 		}
 		c.lock.Unlock()