message: docs: add circle and npm badges to readme
diff: +[![NPM](https://img.shields.io/npm/v/@salesforce/core.svg)](https://www.npmjs.com/package/@salesforce/core)
  +[![CircleCI](https://circleci.com/gh/forcedotcom/sfdx-core.svg?style=svg&circle-token=2377ca31221869e9d13448313620486da80e595f)](https://circleci.com/gh/forcedotcom/sfdx-core)
  +
  # Description
  The @salesforce/core library provides client-side management of Salesforce DX projects, org authentication, connections to Salesforce APIs, and other utilities. Much of the core functionality that powers the Salesforcedx plug-ins comes from this library. You can use this functionality in your plug-ins, too.
  @@ -12,8 +15,8 @@ If you are interested in contributing, please take a look at the [CONTRIBUTING](
  # Related Docs and Repositories
  -* @forcedotcom/cli-packages - Base Salesforce CLI command
  -* @forcedotcom/sfdx-plugin-generate - The generator plug-in for building plug-ins for Salesforce CLI
  +- @forcedotcom/cli-packages - Base Salesforce CLI command
  +- @forcedotcom/sfdx-plugin-generate - The generator plug-in for building plug-ins for Salesforce CLI
  # Using TestSetup
  @@ -101,7 +104,7 @@ describe('Using the built in Sinon sandbox.', () => {
  ### Testing Expected Failures
  -It's important to have negative tests that ensure proper error handling. With *shouldThrow* it's easy to test for expected async rejections.
  +It's important to have negative tests that ensure proper error handling. With _shouldThrow_ it's easy to test for expected async rejections.
  ```typescript
  import { SfdxError } from '@salesforce/core';
  