Revise Model_User::avatar_url() to use "avatar.jpg" as a default, then remove
the six other places this is defined.
Change Search::_build_query_base() from protected to public.
Add Model_Comment::$_sorting, then remove 7 other places this was defined.
Revise Hook_CommentEvent::show_user_profile() to show *viewable* comments only.
Rewrite how all pagination and collection views work.
- add View_Gallery::init_paginator() to do common colllection/pagination tasks.
- revise Controller_Items::action_show() to use it.
- revise Controller_Tags::action_show() to use it.
- revise Controller_Search::action_index() to use it.
- revise Controller_Admin_Users::action_index() to use it.
- revise Controller_Admin_ManageComments::action_queue() to use it.
- revise corresponding views to look for (now unified) $children variable.
Fix use of URL::query() in Controller_Rss and views/search/results.html.
Make search breadcrumbs go from searched album, not root.
- add arg to Breadcrumb::array_from_item_parents() to add a last breadcrumbs.
- add Search::get_breadcrumbs() to use new arg.
- revise Controller_Search::index() to use Search::get_breadcrumbs().
Rename Breadcrumb::instance() --> Breadcrumb::factory().
Merge pull request #441 from shadlaws/fixes_20130701

Fixes 20130701