Move the points hooks admin screen load logic to separate files
Move points hooks AJAX functions to a separate file
Add range to copyright year.
Show the points related screens in the network admin too

See #1
Introduce the 'manage_wordpoints_points_types' capability
Remove redundant styling in hooks.css
Only allow network admins to create and manage points types when network active

See #1
Add manage network points hooks capability, and only set points caps dynamically if not already set

See #1
Make the network points hooks screen manage network-wide hooks

This screen is only present when the plugin is network active.

This also cleans up the `WordPoints_Points_Hooks` class some by
consolodating some of its methods.

Also adds unit tests for parts of `WordPoints_Points_Hooks`.

See #1