documentation: README completness, debug ocrd-tool.json

[tboenig]

Please debug your ocrd_tool.json file.
I found an error:

<report valid="false">
  <error>NO ocrd-tool.json</error>
</report>

You can find the ocrd-tool.json documentation: https://ocr-d.github.io/ocrd_tool

Please check your README file and complet them. Your README is fine but look at your file and compare your's with the ideal README file.

# Name of application


## Introduction
...

## Installation
...

## Usage
...

## Testing
...

Thank you very much.

[crater2150]

The error with the ocrd_tool.json was, that it wasn't there. The repo now contains one which should be correct.

I've also restructured the README, but the "Testing" section is still missing. I'll try to add a testing procedure soon.