move convert dir to tools dir

tools/README.md

@@ -1,11 +1,13 @@
-# Convert the label files to CSV
+# Additional tools
 
-## Introduction
+## Convert the label files to CSV
+
+### Introduction
 To train the images on [Google Cloud AutoML](https://cloud.google.com/automl), we should prepare the specific csv files follow [this format](https://cloud.google.com/vision/automl/object-detection/docs/csv-format).
 
 `label_to_csv.py` can convert the `txt` or `xml` label files to csv file. The labels files should strictly follow to below structure.
 
-## Structures
+### Structures
 * Images
     To train the object detection tasks, all the images should upload to the cloud storage and access it by its name. All the images should stay in the **same buckets** in cloud storage. Also, different classes should have their own folder as below.
     ```
@@ -48,7 +50,7 @@ To train the images on [Google Cloud AutoML](https://cloud.google.com/automl), w
     |    | (same as TRAINING and VALIDATION)
     ```
 
-## Usage
+### Usage
 
 To see the argument of `label_to_csv.py`,
 ```commandline