Merge pull request #1214 from brendanashworth/improve-listbuckets

ListBuckets test & improvement, IsValid{Bucket,Object}Name fix, test, docs

pkg/fs/fs-bucket.go

@@ -69,7 +69,7 @@ func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
 		}
 		// If directories are found with odd names, skip them.
 		dirName := strings.ToLower(file.Name())
-		if file.IsDir() && !IsValidBucketName(dirName) {
+		if !IsValidBucketName(dirName) {
 			continue
 		}
 		metadata := BucketMetadata{