Benchmarking, packaging, and fix issues, tests and perfomance (#797)

### performance
- handling of the very big packet(any size that can be buffered)
- speeding up TCP sessions by using message hints: Added **proto.HasFullPayload** that helps to validate the entire HTTP request, it supports `Chunked` encoding too! Added **proto.HasRequestTitle** and **proto.HasResponseTitle** for validating the beginning of HTTP request. Those methods are used `input_raw.go` with `TCP`.
- supports Keep-Alive: the above functions helps to support keep-alive

### Packaging
- **capture:** engines(capture/doc.go)
- **tcp:** tcp message parser (tcp/doc.go)

### benchmarking
- **capture.BenchmarkPcapDump:** the benchmarks regarding dumping packets in a pcap file
- **capture.BenchmarkPcapFile:** the benchmarks of reading packets from a pcap file
- **capture.BenchmarkPcap:** the benchmarks of parsing packets from the loopback interface with pcap handles
- **proto.BenchmarkHasFullPayload:**: benchmarking this function which validates the HTTP payload
- **tcp.BenchmarkPacketParseAndSort:** benchmarks of parsing and sorting packets
- **tcp.BenchmarkMessageParserWithoutHint:** benchmarks of message reasembling by using `SYN` and `FIN` flag
- **tcp.BenchmarkMessageParserWithHint:** benchmarks of message reasembling by using `proto.HasRequestTitle` and `proto.HasFullPayload` flag

### issues
see linked issues

###  tests
- fixed input raw and engine tests

**Most of the changed of the files, was about using functionalities of** `tcp` **and** `capture` **in existing functionalities**

input_kafka.go

@@ -61,10 +61,7 @@ func NewKafkaInput(address string, config *InputKafkaConfig) *KafkaInput {
 			}
 		}(consumer)
 
-		if Settings.Verbose {
-			// Start infinite loop for tracking errors for kafka producer.
-			go i.ErrorHandler(consumer)
-		}
+		go i.ErrorHandler(consumer)
 
 		i.consumers[index] = consumer
 	}
@@ -75,7 +72,7 @@ func NewKafkaInput(address string, config *InputKafkaConfig) *KafkaInput {
 // ErrorHandler should receive errors
 func (i *KafkaInput) ErrorHandler(consumer sarama.PartitionConsumer) {
 	for err := range consumer.Errors() {
-		log.Println("Failed to read access log entry:", err)
+		Debug(1, "Failed to read access log entry:", err)
 	}
 }
 
@@ -92,7 +89,7 @@ func (i *KafkaInput) Read(data []byte) (int, error) {
 
 	buf, err := kafkaMessage.Dump()
 	if err != nil {
-		log.Println("Failed to decode access log entry:", err)
+		Debug(1, "Failed to decode access log entry:", err)
 		return 0, err
 	}