updated readme options for multi-task, when on multitask options should ...

Config options on the readme needs to be updated, since when wraping config with 'files' cause a multi-task error.

    dox: {
      libdocs :{
        files: {
          src: ['js/lib/'],
          dest: 'docs'
        }
      },
      sourcedocs :{
        files: {
          src: ['js/src/'],
          dest: 'docs'
        }
      }
    },

it should instead look like this:

    dox: {
      libdocs :{
        src: ['js/lib/'],
        dest: 'docs'
      },
      sourcedocs :{
        src: ['js/src/'],
        dest: 'docs'
      }
    },