Add Check For Theme Activation Constant

Allows a developer to skip Roots' Theme Activation step by setting a constant:

define('ROOTS_ACTIVATION', FALSE);
Remove changing media folder from theme activation
screen_icon has been deprecated with WP 3.8
Add notice to theme activation, tidy activation table markup
Generate new roots.pot
Add analytics
Ignore LESS source map
Match wp_register_script function signature

Although the third parameter currently works when false to indicate
no dependancies, it works by side-effect, the function signature uses
an empty array to indicate no dependancies.
Fix gallery link option

Galleries should support three link types:

* Attachment Page (default): [gallery ids="1,2,3"]
* Media File: [gallery link="file" ids="1,2,3"]
* None: [gallery link="none" ids="1,2,3"]
Remove analytics

No longer necessary with https://github.com/blog/1672-introducing-github-traffic-analytics