add block form to subscribers list and profile page

add block form to subscribers list and profile page

I added a small form for blocking users to profiles in the profile
list, and also to the profile page.

I also added an action to handle the results of blocking someone.

This required some changes to the profile list class (so I could
add the block form), so I made them. And the gallery class lets its
subclasses return a subclass of ProfileList for their profile list.

darcs-hash:20081208055511-5ed1f-e2e09986bd3b9cbb6a00a0c6b94f49ea78b7bdab.gz