Views Arguments

Adds Views Argument/Filter/Field helpers:

• Argument validator user_specific: Is user OR has permission. When users can see their own content, and admins can see everyone's content. There's no validator/access check for that.
• Default argument from_callback: From callback function. Enter a callback function to pass the argument value back to the view. Because sometimes you need custom code, but not a whole Views class.
• 'Booleanable' filters, arguments and relationships: Expose a checkbox instead of the filter/argument/relationship. Can disable filter/argument/relationship and adds a yes/no dropdown via exposed filter.
• Any ENTITY field: Creates a hookable views field with a value callback with the relevant entity and context as function arguments.
• Term relationship child_terms: Creates a relationship from a term to all its children. Basic Views comes with a Parent relationship, but not a Children.
• Combined menu items field: Creates a field to combine (custom) link fields in, to make a very simple utility menu, with access checks.
• (1.1) Accessible field: Creates a boolean field, displaying something or nothing, depending on configured access, that you can rewrite to something else. Useful if you want to show that 1 column only to some users.
• (1.2) Display access: Adds a Callback access method to displays, like Page, for custom code to specify fine-tuned access. (Like views_access_callback, but different.)
• (1.2) Handler access: Adds an access callback to all (field, filter, argument, relationship) handlers, for custom code to disable them easily. Requires Views patch!