Add dimension utilities with tests.
Merge branch 'infrastructure' into utils-dimension
Clarify the purpose of the flex: none declaration
Simplify the selector for the `.u-width-` flex fix

The original selector was two selectors. This change reduces it to a single selector.

The only concern at this point is whether relying on the regex selector `*="u-width-"`

We'll go with the current solution until there is evidence that the selector is poor in performance.
Fix indentation, which weren't matching our linting rule
Fix the "Applied to flex items" test to work on iOS

.u-fixture-grow was missing -webkit- prefix and legacy box-flex properties.
Add prefixing to the grow fixture
Merge branch 'utils-dimension' of github.com:mobify/stencil into utils-dimension

Conflicts:
	test/utils/utils-dimension/index.html
Merge pull request #7 from mobify/utils-dimension

Add dimension utilities with tests.