Add MIT License
Remove example SCSS and CSS

Clean up the repo and avoid including compiled assets in the source
code.
Remove example demo
Remove watch script

No longer necessary now that the examples and compiled assets are gone.
Remove support for "push" classes

Remove these classes because they're not of great utility and they add
extra complexity to the SCSS and HTML (in terms of overriding at various
breakpoints).

Rename the "scss/_grid-helpers.scss" file to "griddle-build".
Reorganize core Griddle SCSS file

Update the comment format to match the one I use for normalize.css and
the SUIT componenets.

`@import` the griddle-build file into `griddle.scss`. Makes it a bit
easier to get up and running.
Add `component.json` for Bower
Reflect latest changes in README
Add CHANGELOG
Minor README adjustments