Use parent's author as "to" user for mod replies to modmail PMs.
install-reddit: Add libpcre3-dev for traffic scripts.
Add pixel and click redirect server.
validator: Protect from ValueError in VCommentIDs.
Prefs: allow defaulting to new window opens

In general, non-power users tend to not open links in new tabs.  This provides
problems for sites like ours, since we end up with a very high bounce rate -
people click on a submission link, end up on some other interesting site, and
forget all about how they got there.  If that link instead opens in a new
window (tab), that problem is solved.

This is a pretty common behavior on link-aggregation sites, eg Google News.

We definitely don't want to change this for existing users, because that
creates a very confusing change.  Additionally, we're not sure if we will want
to keep this around for everyone, so rather than change the default and
backfill preferences, we're just setting it for anonymous users and new user
registrations - wrapped in a feature flag for easy alteration.
Modqueue: add reply button to comments

[A suggestion][0] from /u/rotorcowboy.

`printablebuttons.html` contains logic that supresses the reply button for
comments that show up on profile pages.  This appears to have incidentally been
included for the modqueue, per 0fe8f70 and prior code, so I just removed it and
massaged a few other things to make everything work.

This also adds comment reply capabilities to the various modqueue-like subpages
(reports, spam, edited).

[0]: http://www.reddit.com/r/ideasfortheadmins/comments/2ju3dg/add_a_reply_button_to_comments_in_the_modqueue/
Fix handling nonexistent welcome message templates
New windows pref: disable default-on for phones

See 0b7deff for some background.

This ends up being particularly annoying on phones, so we're changing the
default back for them.  An overall revert or an inclusion of tablets are both
stil in the cards, but for right now we need to fix this.

This affects both the desktop site and .compact.

@umbrae gets the credit for writing this; I just tested it and am committing.
Add hook for self-post/comment edit
Merge branch 'master' of https://github.com/reddit/reddit