Reorganize directory structure.
Remove unnecessary class from arrange tests.
Restore component and util grouping directories.
Ignore .DS_Store hidden files
Merge spacing and layout utils from master.
Merge branch 'master' into improve-dir-structure

Conflicts:
	test/utils/utils-layout/utils-layout.scss
Rename test/tests to tests/visual.
Add consistent line heights and fix missing semi-colon
Merge pull request #23 from mobify/improve-dir-structure

Improve directory structure