buf: fix improper alignment of bombardier's fields

Due to improper alignment program crashed on ARM and x86-32
architectures.

Fixes #18.

bombardier.go

@@ -15,16 +15,24 @@ import (
 )
 
 type bombardier struct {
+	bytesTotal, bytesData int64
+
+	// HTTP codes
+	req1xx uint64
+	req2xx uint64
+	req3xx uint64
+	req4xx uint64
+	req5xx uint64
+	others uint64
+
 	conf           config
 	requestHeaders *fasthttp.RequestHeader
 	barrier        completionBarrier
 	workers        sync.WaitGroup
 
-	bytesTotal int64
-	bytesData  int64
-	timeTaken  time.Duration
-	latencies  *stats
-	requests   *stats
+	timeTaken time.Duration
+	latencies *stats
+	requests  *stats
 
 	client   *fasthttp.Client
 	doneChan chan struct{}
@@ -34,14 +42,6 @@ type bombardier struct {
 	reqs  int64
 	start time.Time
 
-	// HTTP codes
-	req1xx uint64
-	req2xx uint64
-	req3xx uint64
-	req4xx uint64
-	req5xx uint64
-	others uint64
-
 	// Errors
 	errors *errorMap