(Bug 1867) Add reading filter module to core2

* adds in a SubscriptionFilter class to S2
* adds in a built-in function to S2, journal_subscription_filters, returning a list of
  SubscriptionFilters
* adds in appropriate module variables in core2
* adds a "print_module_readfilters()" S2 function to print the module; it uses the standard
  module list printing
* adds "property use module_readfilters_group;" to all propgroup modules sections in layouts

Things to double check:

* Test that private filters do not show to people other than the journal owner; I've tested this but
  it's very critical.
(Bug1867) Fix readfilters module ordering

Fix the readfilters module ordering for Blanket and EasyRead.
(Bug 1867) Review code clean up

This patch:

* Standardizes the module name around subscription filter; that's what they're called
  in other areas of the site, so we should be consistent.
* Standardized the SubscriptionFilter class to be consistent in naming; it now has
  a string url var instead of a string link, because the Link class seemed overkill
* Abstracts away the id of the Subscription filter; we can add it in if we need it later
* Improves the logic of adding a filter to the list of filters displayed
(Bug 1867) Add a manage link to the filter module

Implements the same way other management links have been implemented.
(Bug1867) Improve filter module print checks

Now the module checks to see if it should print:

* It shouldn't print for communities or for syncdication journals
* It shouldn't print if there are no filters for it to print
(Bug1867) Filter module shouldn't show for comms

Makes it so the filter module doesn't show up in the
theme customization wizard for communities, as they
cannot use it.
(Bug 4755) Initial layout and four color themes by momijizukamori
(Bug 4755) Optimized preview images
(bug 4908) change target for redirect to .bml-less version

also, while i'm at it, correct a grammatical error in one of the text
strings!
(bug 4897) UNTESTED: add hook for dreamwidth.org specific text

the hook itself is in the dw-nonfree patch forthcoming. THIS IS NOT
TESTED, since my 'hack isn't set up to do payments, so it may not work
or the formatting may be weird!
Bug 4240 - Profile module: match text links with icon links
http://bugs.dwscoalition.org/show_bug.cgi?id=4240
-- Use text strings from en.dat instead of Core2 props
-- Rephrase some strings
-- Remove no obsolete props from Core2
-- All credit goes to @jeshyr
Bug 4845 - subscribing to a comm gives incorrect text on the confirmation screen
http://bugs.dwscoalition.org/show_bug.cgi?id=4845
-- Don't add extra text for communities
(bug 4908) correct changed string

Oops.
(Bug 4755) Property name clean-up, theme organization
Merge pull request #296 from rahaeli/bug-4908

(bug 4908) change target for redirect to .bml-less version
(Bug 4229) Remove redundant credit, adjust theme name
Merge pull request #306 from afuna/meta-tweaks-bug4229

(Bug 4229) Remove redundant credit, adjust theme name
Bug 4247 - Clarify invite notification and options on /manage/invites
-- Rephrase link to /manage/invites in notifications
-- Rephrase Manage Invites title in several locations
-- Add explanatory text on /manage/invites and /community/manage
-- Rephrase various string on /manage/invites
-- Add text and list of links on success page
-- Add line-breaks
-- Downgrade subheaders to H2
-- Change UL to DL for community lists
-- Move dead string to deadphrases
Bug 4937 - Database: visited links not getting hover colors in entries
http://bugs.dwscoalition.org/show_bug.cgi?id=4937
-- Always put hover link after visited link
Merge pull request #310 from ninetyd/bug4937/database_fix_link_order

Bug 4937 - Database: visited links not getting hover colors in entries