feat(input): support varying size

Just like the buttons in #17, we'll now allow the usage of sizing
classes for inputs.

Closes #19
docs(browser support): document supported browsers and devices

Closes #30
docs(readme): add license section
refactor(dropdown): fix inconsistency in dropdown-options

The dropdown-options was (inconsistently) using 'items' as the
attribute for looking up the repeat expression.
With this commit, this attribute has been renamed to 'options'.

Fixes #22
Merge branch 'issue-22'
Merge branch 'issue-19'
feat(grid): add support for column ordering

Support column ordering by using prefix-pull-*-* or prefix-push-*-*
classes. They will change left and right CSS attributes, respectively.

Closes #24