moved fields requiring 64-bit alignment to start of struct

several data structures had a pointer at the start of the struct
on some 32-bit systems, this causes the remaining fields no longer
be aligned on 64-bit boundaries

the fix identifed by @pmezard is to put the counters first in the
struct, which guarantees correct alignment

fixes #359

index/firestorm/stats.go

@@ -17,12 +17,12 @@ import (
 )
 
 type indexStat struct {
-	f                                 *Firestorm
 	updates, deletes, batches, errors uint64
 	analysisTime, indexTime           uint64
 	termSearchersStarted              uint64
 	termSearchersFinished             uint64
 	numPlainTextBytesIndexed          uint64
+	f                                 *Firestorm
 }
 
 func (i *indexStat) statsMap() map[string]interface{} {

index/upside_down/stats.go

@@ -17,12 +17,12 @@ import (
 )
 
 type indexStat struct {
-	i                                 *UpsideDownCouch
 	updates, deletes, batches, errors uint64
 	analysisTime, indexTime           uint64
 	termSearchersStarted              uint64
 	termSearchersFinished             uint64
 	numPlainTextBytesIndexed          uint64
+	i                                 *UpsideDownCouch
 }
 
 func (i *indexStat) statsMap() map[string]interface{} {

index_stats.go

@@ -16,9 +16,9 @@ import (
 )
 
 type IndexStat struct {
-	i          *indexImpl
 	searches   uint64
 	searchTime uint64
+	i          *indexImpl
 }
 
 func (is *IndexStat) statsMap() map[string]interface{} {