Fix badges and add to RTD

[nozavroni]

• Some of the badges aren't rendering correctly on phpcsv.com
• Add all badges to RTD docs

.. image:: https://coveralls.io/repos/github/nozavroni/csvelte/badge.svg?branch=master
   :target: https://coveralls.io/github/nozavroni/csvelte?branch=master

.. image:: https://travis-ci.org/nozavroni/csvelte.svg?branch=master
   :target: https://travis-ci.org/nozavroni/csvelte

.. image:: https://scrutinizer-ci.com/g/nozavroni/csvelte/badges/quality-score.png?b=master
   :target: https://scrutinizer-ci.com/g/nozavroni/csvelte

[nozavroni]

Implemented and finished!