Chore/eslint configs

[nobitagit]

This PR upgrades Eslint version, fixes the existing errors and applies the recommended react configuration.
This is handy so that anyone forking this project will start from a clean slate on master.

Current master:

$ eslint src

...../react-annotation/src/components/Handle.js
  1:8  error  'React' is defined but never used  no-unused-vars

...../react-annotation/src/docs/Types.js
  236:1  error  Expected indentation of 12 spaces but found 10  indent
  237:1  error  Expected indentation of 12 spaces but found 10  indent
  243:1  error  Expected indentation of 12 spaces but found 10  indent
  244:1  error  Expected indentation of 12 spaces but found 10  indent
  265:1  error  Expected indentation of 12 spaces but found 10  indent
  266:1  error  Expected indentation of 12 spaces but found 10  indent
  267:1  error  Expected indentation of 14 spaces but found 10  indent
  268:1  error  Expected indentation of 14 spaces but found 10  indent
  269:1  error  Expected indentation of 16 spaces but found 10  indent
  270:1  error  Expected indentation of 16 spaces but found 10  indent

✖ 11 problems (11 errors, 0 warnings)
  10 errors and 0 warnings potentially fixable with the `--fix` option.

This branch:

$ eslint src
✨  Done in 1.29s.

I ran the build locally but didn't include the output (bundle.js) in the PR, if it's needed I can quickly add it on top of this branch.