Update README.md for webpack 2

[sidraval]

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?
Currently, the babel loader section of the webpack 2 documentation is outdated.

What is the new behavior?
I've fixed the links in the readme to point to the new webpack documentation, and updated the examples to webpack 2 style. I also incorporated the logo changes &c. from #355

Does this PR introduce a breaking change?

• Yes
• No

Other information:
I just went through a webpack 2 setup on a project, noticed this documentation was out of date, and thought I'd change it as I went!

[codecov]

Codecov Report

Merging #402 into 7.0 will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              7.0     #402   +/-   ##
=======================================
  Coverage   81.87%   81.87%           
=======================================
  Files           6        6           
  Lines         160      160           
  Branches       35       35           
=======================================
  Hits          131      131           
  Misses         13       13           
  Partials       16       16

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[danez]

Thank you very much, this is awesome.