Collectors in parallel (#74)

* Provide info to CollectorManager whether the collector can be executed in parallel with others

* Split serial and parallel collectors. Read in parallel first

collectors/likwidMetric.go

@@ -177,6 +177,7 @@ func getBaseFreq() float64 {
 
 func (m *LikwidCollector) Init(config json.RawMessage) error {
 	m.name = "LikwidCollector"
+	m.parallel = false
 	m.initialized = false
 	m.running = false
 	m.config.AccessMode = LIKWID_DEF_ACCESSMODE