Merge branch 'release/v0.9.0'
Merge tag 'v0.9.0' into develop

v0.9.0
feat(Functions): implements `escape-css` function
chore: bumps the version
refactor(sass): `arkush` -> `arkush/extensions`
feat(AssetManager): implements `dimensions` method
refactor(Functions): uses dimensions method from AssetManager
fix(sass/mixins/inline-image): properly names the mixin
fix(gemspec): removes Ruby Racer dependency
chore: bumps the version
Merge branch 'release/v0.9.2'

Conflicts:
	arkush-extensions.gemspec
	lib/arkush/extensions/functions.rb
	lib/arkush/extensions/version.rb