Merge pull request #134 from rvoicilas/master

Fix typo Invitiation -> Invitation
invitation requests: <em> emails
tweak story submission guidelines
add Tag.active scope to deprecate tags without removing them
message view: show admin/moderator status of sender
show story downvoting usernames to moderators to detect problems

such as voting rings or users downvoting things instead of filtering
tags
reserve "moderator" and "moderators" usernames
story submission: link to previously submitted url for recent stories

if there is only one error and the story has a already_posted_story,
show a custom error dialog that links to that story.  if there are
other errors, show the standard error dialog.

closes #135
rename stories.short_id index to avoid conflict in non-mysql dbs

this was never added from a migration anyway, so this is just for a
rake:schema:load
fix test after mailing_list_enabled -> mailing_list_mode change
move initial upvote of submitted story to Story model
remove story downvoting, add story hiding

stories should either be reported for spam (coming later), upvoted,
or left alone rather than being downvoted for being uninteresting.
since users don't like leaving uninteresting things alone, they can
now hide stories from their view without affecting the story's
score.

hiding is implemented as a Vote with its vote set to 0 and the
reason set to "H"

add a /hidden url which shows all of a user's hidden stories

while i'm here, simplify Vote guts and add some tests to make sure
all the flip-flopping stuff works right
move story voter arrow down and tighten up list since downvote is gone
check story tag permissions on editor, not creator
update a user's unread message count after bulk-delete

only count messages that are both unread and undeleted
diffbot appears to be formatting results properly now
simplify rss <link> generation
swap out /newest link for /recent
if a user has had a story moderated in the past 5 days, show guidelines
auto-apply slides tag to speakerdeck.com