(Bug 4784) Use default value only if we haven't POSTed yet

Also explain what the default is meant for, to distinguish it from other
ways of setting the visible form field value
(Bug 4832) Rename old-style request objects to $apache_r

For greater clarity, and to make it easy to hunt them down later.

Also removes in a couple places where they were initialized but not
used.
(Bug 4832) Fix status code
Bug 4657 - comment edited notification does not appear under Entries & Comments filter
http://bugs.dwscoalition.org/show_bug.cgi?id=4657
-- Add edit comment notif to comments filter in inbox
Bug 4834 - Summertime: resource credit missing from Tennis Court
http://bugs.dwscoalition.org/show_bug.cgi?id=4834
Bug 4777 - Abstractia: header_background not actually implemented
http://bugs.dwscoalition.org/show_bug.cgi?id=4777
(Bug 4831) Remove one of the two colons after Diagnostics.
(Bug 4783) Skip paid expiration warnings for deleted users.
Bug 4835 - Librarian's Dream: wrong URLS for backgrounds
http://bugs.dwscoalition.org/show_bug.cgi?id=4835
-- Update image URLs
-- Move common image to /commons
Bug 4836 - Librarian's Dream: header_background_image doesn't work
http://bugs.dwscoalition.org/show_bug.cgi?id=4836
-- Remove CSS overrides
Bug 4838 - Librarian's Dream: links aren't in the correct order/use different selectors
http://bugs.dwscoalition.org/show_bug.cgi?id=4838
-- Reorder links
-- Use same selectors for links
Bug 4785 - Background images not showing in Librarian's Dream
http://bugs.dwscoalition.org/show_bug.cgi?id=4785
-- Remove CSS override
Merge pull request #211 from afuna/apache-request-status-bug4832

(Bug 4832) Define status code, use $apache_r
Merge pull request #212 from ninetyd/bug4657/inboxfilter_edits

Bug 4657 - comment edited notification does not appear under Entries & C...
Merge pull request #214 from ninetyd/release-1.13

Bug 4834 - Summertime: resource credit missing from Tennis Court
Merge pull request #215 from ninetyd/bug4777/abstractia_headeroption

Bug 4777 - Abstractia: header_background not actually implemented
Merge pull request #216 from alierak/support-diags-bug4831

(Bug 4831) Remove one of the two colons after Diagnostics.
Merge pull request #217 from alierak/paidstatus-bug4783

(Bug 4783) Skip paid expiration warnings for deleted users.
Merge pull request #218 from ninetyd/bug4835/librarian_urls

Bug 4835 - Librarian's Dream: wrong URLS for backgrounds
Merge pull request #219 from ninetyd/bug4836/librarian_headerimage

Bug 4836 - Librarian's Dream: header_background_image doesn't work