Replace parsing by 'material-colors-object' module

[amercier]

Hi @shuhei!

TL;DR: This PR replace its own parsing by using the material-colors-object.

Description

I made material-colors-object which parses colors from the Official Material Design Documentation page. I think this package is not redundant with yours, it could actually allow separation of concerns pretty neatly:

• material-colors-object would parse the official documentation and expose a raw Javascript object. It needs to be updated every time the documentation format or content change.
• material-colors would use data from material-colors-object and expose .css, .scss, etc. files to coders. It wouldn't need to be updated every time the documentation format or content change.

Notes

• The official documentation has been updated since the release of material-colors. URL https://material.io/guidelines/style/color.html now redirects to https://material.io/design/color/.

• The official documentation doesn't contain light and dark text information anymore. That is why material-colors-object doesn't expose it. This PR doesn't intent to break backward compatibility, that's these colors have been added statically in lib/compat.json. The only drawback is that "compatiblity" colors are positioned after Black & White (that's what this PR contain changes in .css, .scss, etc files. See dist/colors.json diff for a clear picture.

• Format of material-colors-object's object differs a little bit from what fetch() returned, so I updated the json grunt task in order to maintain backward compatibility.

• Official documentation now use Gray instead of Grey, so I updated the json grunt task in order to maintain backward compatibility.

• material-colors-object also contain light and dark variant for each colors (which are shown in https://material.io/tools/color/#!/). I will post another PR to add these variants in material-colors later. (Edit: done in #23)

[shuhei]

Hi @amercier, this is great! Thanks a lot for updating the data fetching and taking care of backward compatibility.

I'll leave one minor comment about versioning. Everything else looks good to me!

[shuhei]

Thanks for updating!