[HOTFIX] Unrelated bug fix for twitter module, defined constants for default variables (name and count).
[#11630] Initial module for social links added.
Merge branch 'master' into 11630-social-links-module

Conflicts:
	themes/agov_base/css/global.css
	themes/agov_base/sass/global.scss
[#11630] Help documentation updated.
[#11630] Added new social links module to install profile.
[#11630] Removed previous social menu module and menu_attributes dependency
[#11630] CSS fixes for icon display.
[#11630] Removed unneeded code that added accessible items for old menu module.
[#11630] Removed globals and replaced with a dedicated function.
[#11630] Fixed DCS problems.
Merge pull request #111 from previousnext/11630-social-links-module

11630 social links module