Django-phone-field

Define a hash for `PhoneNumber` objects to fix 13

Addresses 8 where there's no good way to hide the text before the extension input. Please make sure the new html doesn't affect your CSS before upgrading. What used to be `.ext` is now `<span class="phone-field-ext">.ext</span>`

Fix 7 where an exception is thrown when using `null=True` and rendering a form

Added support for setting individual attributes for the phone number and extension widgets