Revamp buggy Align component

Remove unsupported Align component features, support horizontal alignments and update code style. Incorporates the changes in #54. This makes the component pretty small; we should consider deprecating it in favour of direct use of flexbox.

Status: **Ready to merge**

Reviewers: **@kpeatt @jeffkamo**
Ticket: **Fixes #45**

## Changes
- Remove the ability to individually align child items due to poor support for `align-selft`. In fact, the `c-align__item` sub-component is completely removed in favour of alignment modifiers on the parent.
- Add root-level modifiers for top, bottom, left and right alignment of child items.

## How to test-drive this PR
- Check out the new tests.