The change introduced in #325 incorrectly configured the Runner to start with --watchAll enabled. I'll take some of that blame for the unclear API. To use --watchAll you need to set true, true which isn't clear. 😞

Changes proposed in this PR:

• Change the watch mode flag from a Boolean to an enumeration: none, watch, watchAll
• Properly start the Runner with --watch and --watchAll
• Detect the error message when --watch is not supported and restart with --watchAll

Changes not proposed in this PR:

• No setting to "always use --watchAll" since we can detect when --watch fails
• Moving the error message detection into jest-editor-support. I know cpojer wants to add integration tests to make sure we catch if the text changes.

Testing:

• Manually tested using a workspace without a git or hg repo:

  index.test.js:

  describe('Test suite', () => {
    it('Test', () => {
      expect(1).toBe(2);
    })
  })

• Tests have been updated with a few redundant test cases removed

This will resolve #327.