Update requirements to support React 16

[mjclawar]

It seems like multiple requirements do not support newer versions of React 16. Some packages, like react-syntax-highlighter have breaking changes for updates.

This should be the final piece for dash-core-components to support React 16 outside of updating dash-renderer.

This will be updated when I find additional packages that need to be updated.

Updates

• 2018-02-24 react-virtualized-select is causing issues in Dropdown.react.js. All other packages are working fine now with a monkey-patched React v15.6 in dash-renderer on https://github.com/mjclawar/dash-core-components/tree/164-react-16

This line: https://github.com/mjclawar/dash-core-components/blob/e99bff257859868ed1dffbedcb8286418c1e209f/src/components/Dropdown.react.js#L4 was causing a React version error that imported an older React version. Updated to pulling directly from the umd build as

import ReactDropdown from 'react-virtualized-select/dist/umd/react-virtualized-select';

Packages that will be updated:

• react-dates to "16.3.2"
• react-dropzone to "4.2.8"
• react-markdown to "3.2.1"
• react-select to "1.2.1"
• react-select-fast-filter-options to "0.2.3"
• react-syntax-highlighter to "7.0.0"
• react-virtualized-select to "3.1.3"
• react and react-dom as peerDependencies "^15.4.0 || ^16.0.0"

Packages that will be added

• style-loader and css-loader for importing the css as required by the new react-dates