v0.0.2: Leverage ACF for custom fields

* Brought in some useful constants from 10up's `wp-plugin` grunt scaffold
* Advanced Custom Fields plugin included in theme
* Added XML and PHP versions of exported ACF configuration
* Admin CSS styles added, registered and enqueued
* SCSS rules added for some minor Artwork edit screen styling adjustments
* Grunt used to build CSS and JS for release
* Bump to 0.0.2
Improve input process, and add an action to render artwork on the site

Editing improvements:

* Upgrade ACF submodule to fix bug where conditional logic won't fire on a CPT with no Editor
* List taxonomies in columns on Artwork post list admin screen
* Add media queries to improve layout of image/video selection area
* Use default WP editor, instead of a custom field

Render artwork on the front-end, on archives and single page view

* Hook into `the_content` to render basic data by default, without any theme editing required
* Render thumbnail-size image in archives, and full-size image in single-page view
Update ACF submodule & remove date stamp from built files

Housekeeping tasks:

* Having the timestamp just makes for nastier diffs with no functional benefit. Removing them makes life simpler.
* ACF updated to latest (approaching the release of v4.2)
* .gitignore has been augmented with other common non-sourcecode file patterns
Adjust styling for artwork selection fields

* Unneeded extra top padding removed.
* Layout now changes to one-column at 900px, the same breakpoint where the side menu auto-collapses. This provides a more unified responsive editing page.
Update Advanced Custom Fields configuration

Several changes have been made after discussing the project with Emily.
This updated config reflects the latest "approved" fields.
Load fields from config from export when lite mode is enabled

If `define( 'ACF_LITE' , true );` is specified in `wp-config.php` or another settings file, then the PHP file containing the exported Advanced Custom Fields configuration will be imported
Fast-forward ACF sub-module to latest
Update ACF
Expose custom taxonomy list queries as a class method

We need access to the list of a post's custom Media and Dimensions taxonomy terms from a number of places. Abstracting the construction of taxonomy term lists into a public method both reduces internal code duplication and provides a clean external API from the theme layer.