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**

protocol.go

@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"crypto/rand"
 	"encoding/hex"
-	"strconv"
+	"fmt"
 )
 
 // These constants help to indicate the type of payload
@@ -48,37 +48,9 @@ func payloadScanner(data []byte, atEOF bool) (advance int, token []byte, err err
 
 // Timing is request start or round-trip time, depending on payloadType
 func payloadHeader(payloadType byte, uuid []byte, timing int64, latency int64) (header []byte) {
-	var sTime, sLatency string
-
-	sTime = strconv.FormatInt(timing, 10)
-	if latency != -1 {
-		sLatency = strconv.FormatInt(latency, 10)
-	}
-
 	//Example:
-	//  3 f45590522cd1838b4a0d5c5aab80b77929dea3b3 1231\n
-	// `+ 1` indicates space characters or end of line
-	headerLen := 1 + 1 + len(uuid) + 1 + len(sTime) + 1
-
-	if latency != -1 {
-		headerLen += len(sLatency) + 1
-	}
-
-	header = make([]byte, headerLen)
-	header[0] = payloadType
-	header[1] = ' '
-	header[2+len(uuid)] = ' '
-	header[len(header)-1] = '\n'
-
-	copy(header[2:], uuid)
-	copy(header[3+len(uuid):], sTime)
-
-	if latency != -1 {
-		header[3+len(uuid)+len(sTime)] = ' '
-		copy(header[4+len(uuid)+len(sTime):], sLatency)
-	}
-
-	return header
+	//  3 f45590522cd1838b4a0d5c5aab80b77929dea3b3 13923489726487326 1231\n
+	return []byte(fmt.Sprintf("%c %s %d %d\n", payloadType, uuid, timing, latency))
 }
 
 func payloadBody(payload []byte) []byte {
@@ -89,19 +61,21 @@ func payloadBody(payload []byte) []byte {
 func payloadMeta(payload []byte) [][]byte {
 	headerSize := bytes.IndexByte(payload, '\n')
 	if headerSize < 0 {
-		headerSize = 0
+		return nil
 	}
 	return bytes.Split(payload[:headerSize], []byte{' '})
 }
 
-func payloadID(payload []byte) []byte {
-	idx := bytes.IndexByte(payload[2:], ' ')
+func payloadID(payload []byte) (id []byte) {
+	meta := payloadMeta(payload)
 
-	if idx == -1 {
-		return []byte{}
+	if len(meta) < 2 {
+		return
 	}
-
-	return payload[2 : 2+idx]
+	// id is encoded in hex, we need to revert to how it was
+	id = make([]byte, 20)
+	hex.Decode(id, meta[1])
+	return
 }
 
 func isOriginPayload(payload []byte) bool {