v2.0.0

[chris-pearce]

Mostly this:

• General typo and code example fixes.
• Removed all smart quotes.
• Remove all references to the Scally CSS Framework as I want these guidelines to not be tied to any particular framework/library.
• Changed the empty line rule that comes after: Commenting -> Partial Heading to be one (1) empty line not two (2).
• Removed the non-mandatory sections: @author and @created from: Commenting -> Partial Heading as I don't see any value in this convention anymore. It's better to use source control e.g. Git for this information.
• Removed the Commenting -> BEM Modifier Markers section as I don't see any value in this convention anymore. It's obvious a selector is a BEM modifier from the two (2) hyphens in its name e.g. .c-card--compact—certainly if a BEM modifier isn't obvious from the code alone then go ahead and add some comments but no need to use the "Modifier" marker convention.
• Removed the Naming Conventions -> Mixins And Functions section as it was mostly referring to the Scally CSS Framework.
• Removed the Naming Conventions -> Spelling section so it's scalable to any team worldwide, basically this should be decided upon by the team.
• A few updates to the Tooling section.
• Created a .version file.
• PR's addressed:
  • fix typo #17

@kllevin could you take a look when you can? Thanks.