Bump the file size limit to 2 MB

The largest .cc file in the chromium tree is 1157895 bytes

Fixes #107.

Change-Id: I4c1013366168ae1a31dc456fb423a289126274dd
diff --git a/cmd/flags.go b/cmd/flags.go
index 3222d5d..27cca86 100644
--- a/cmd/flags.go
+++ b/cmd/flags.go
@@ -38,7 +38,7 @@
 }
 
 var (
-	sizeMax     = flag.Int("file_limit", 128*1024, "maximum file size")
+	sizeMax     = flag.Int("file_limit", 2<<20, "maximum file size")
 	trigramMax  = flag.Int("max_trigram_count", 20000, "maximum number of trigrams per document")
 	shardLimit  = flag.Int("shard_limit", 100<<20, "maximum corpus size for a shard")
 	parallelism = flag.Int("parallelism", 4, "maximum number of parallel indexing processes.")
diff --git a/toc.go b/toc.go
index 97799a2..c956e94 100644
--- a/toc.go
+++ b/toc.go
@@ -38,7 +38,8 @@
 // 6: Include '#' into the LineFragment template
 // 7: Record skip reasons in the index.
 // 8: Record source path in the index.
-const FeatureVersion = 8
+// 9: Bump default max file size.
+const FeatureVersion = 9
 
 type indexTOC struct {
 	fileContents compoundSection