v1.0.1 release candidate 2

Improvements since v1.0.0:

Contracts

• SECURITY FIX: changeHat should collect debt correctly
• Standalone (MCD) rDAI contract for supporting MCD rDAI deployment

Testing

• Improved test coverages
• Added solidity-coverage

Documentations

• Added materials to the developers documentation section

Dev process

• Updated to latest of the dependencies
• Added github "Node CI" and 'Node.js Package" workflows