Enqueue client js in admin
Merge pull request #473 from tlovett1/feature/admin-js

Register client js in admin.
Create global function to check read permissions on objects.
Create global function to check edit permissions on objects.
Deprecate permission check methods in Post controller in favor of global functions.
Update permission checks in Post controller to use new global functions.
Restructure logic in read and edit permission checks to return correct response.
Update read permission checks in Post controller to use global function.
Replace edit permission check in Post Meta controller with global function.
Remove Post Meta check edit permission method in favor of global.
Correct spelling of permission variable.
Replace inline edit capability checks with json_check_edit_permission().
Add json_check_create_permission function.
Add json_check_delete_permission function.
Replace inline permission checks with create and delete permission check functions.
Change to object based permission checks for more flexibility.

Create new function json_check_post_permission.
Remove previous json_check_{capability}_permission functions.
Update permission check function names in Posts and Meta routes.
Merge branch 'split-permission-checks' into split-comment-class

Conflicts:
	lib/class-wp-json-posts.php
Applied fix from 9d4af6 to get parent of comment.