Update autoprefixer map option

Accommodate the grunt-autoprefixer 0.8.0 options refactor
by passing an object (instead of string) to map option
a la nDmitry/grunt-autoprefixer@c658fb7
and nDmitry/grunt-autoprefixer@1b7af91
Merge pull request #1082 from fullyint/update-autoprefixer

Update autoprefixer map option
add _responsive-embed.less
Merge pull request #1083 from jholl/patch-1

add _responsive-embed.less
Splits mixins into separate imports, fixes import order.
Make WP_ENV check a positive if statement to improve semantics and readability
Merge pull request #1085 from CFXd/make-wp_env-check-positive-if-statement

Make WP_ENV check a positive if statement to improve semantics and readability
Remove extra forward slash after navbar home_url()
Merge pull request #1096 from CFXd/remove-extra-fwd-slash-after-navbar-home_url

Remove extra forward slash after navbar home_url()
use WP HTML5 markup for captions instead of Soil

Use add_theme_support to enable native HTML5 captions and add caption styling to wp-caption-text.
Merge pull request #1105 from kevinlisota/html5-captions

use WP HTML5 markup for captions instead of Soil
Move <main> and .sidebar markup out of PHP

Add more efficient LESS with variables

Add new line to _variables.less

Add sidebar class to body element instead of main element

Change body sidebar class to .sidebar-active

Change body sidebar class to .sidebar-primary

Correct spacing issues
Remove unnecessary string concatenation.
Check sidebar conditional tag exists

Return false for non-existent conditional tags. Fixes #993
Merge pull request #1113 from roots/conditional_checks

Check sidebar conditional tag exists
Runs platform agnostic postinstall. Closes #1078

Global node binary is used to execute bower.
Global grunt binary (from grunt-cli) is used to run `dev` task.
updated package.json to use version 1.3.9 or greater
Merge pull request #1118 from LibLogic/master

updated package.json to use version 1.3.9 or greater
Only load GA in production environment

Loads Google Analytics when `WP_ENV` is 'production'
Otherwise it passes `ga()` arguments as an array to `console.log()`

Also sets cookie domain to be auto configured.
Always load GA snippet when not in production