Delete Notes

Notes can now be deleted (by administrators) from the organization page
using AJAX.
Dynamic "No notes"

Upon deleting the last note from an organization via AJAX the "No notes"
message will properly display.
getElementsByClassName Legacy Support

Added hooks to shared.js to add getElementsByClassName support to
browsers too old to have such support (such as IE7/8).
Comment Typo

Corrected a typo in a comment in notes.phtml ("form" => "from").
Schema Update

In order for users to be deletable the fields that hold `users` foreign
keys in `organization_notes` must be NULLable.
Notes Nullable

Edited organization notes-related functionality to support associated
users being NULL (which will be a consequence of user deletion).
Delete Users

Users can now be deleted from their "Edit User" page.

A user may delete another user if they are not trying to delete
themselves and they are an administrator, or they are a superuser of the
organization the target user is a member of.

This is laid out in detail in person.php lines 47-63.