Removed body.active_admin encapsulation for global-reset.
Removed body.active_admin encapsulation for other active admin styles..
make generated files singular instead of plural

Closes #2249
remove unnecessary backslashes in tests
update form builder to only use return val if it's a string

This closes #2192 by updating the fix for #887 to simply drop any
return value that isn't a string.
Merge 'unencapsulate-css-global-reset' of github.com/tinynumbers/active_admin

Conflicts:
	app/assets/stylesheets/active_admin/_base.css.scss
	lib/generators/active_admin/assets/templates/3.1/active_admin.css.scss
add modal dialog w/ custom form inputs to Batch Actions
styled inline modal forms to match active admin
bug fixes

+ variables in the loop were bleeding over
+ regex was inaccurate
+ make HTML building code more readable
CSS update

remove wasted space, as well as unused CSS rules