[core] Normalizing files whitespace/styleguide

[SBoudrias]

What?

Yeoman generates a lot of file for the user. A big issue currently is that all files are copied as is and ain't modified to match the user/team coding style guide.

It would be greatly appreciated from Yeoman user if they were able to define styling constraint in the .editorconfig file and simply see the style applied to new files.

Feature

• Parsing .editorconfig files to extract config - respecting nested rules, root rules, etc.
• Normalizing multiple file type whitespaces
• This could be easily be made in a standalone module (Yay!)
• [extra] beautifying code based on common coding styleguide

Prior art

• Parsing editorconfig https://www.npmjs.org/package/editorconfig
• The styling should be applied inside a file-util (Yeoman file system) write filter https://github.com/SBoudrias/file-utils#write-filters
• generator-bbb have a very basic implementation of the functionality: https://github.com/backbone-boilerplate/generator-bbb/blob/master/lib/generators/base/bbb-generator.js#L26-L32
• Detect-Indent - possible fallback when no .editorconfig is present

Notice

We're strongly considering changing our file-system. If this happens, write filter would simply be gulp plugins. So if someone want to work on this one, it might make sense to investigate this avenue rather than fixing our currently broken file system.