Fix group matching SQL query

The check there is intended for the :members_mods_and_admins level, which is not automatically checked for normal users. Instead, the :everyone level is the one used, which would always fulfill the "alias_level in :levels" check.

This changes the :everyone level to :members_mods_and_admins, which was originally intended.
Change to case-insensitive matching in group @name matching
BUGFIX: site_contact_username was case-sensitive
BUGFIX: not seeding welcome topic
Allow CORS on .ico files. Should help with Favcount.js
FIX: Allow Favcount to be used with CORS. I've submitted this upstream
too:

https://github.com/chrishunt/favcount/pull/8
BUGFIX: clicking the logo when the homepage was /categories or /top would fail
FIX: Could navigate back to "Preferences" from "Change Email"
Bump favcount.js to v1.5.0

We've already made the CORS changes in our copy of favcount, but we
should bump the version to match upstream.
Merge pull request #1855 from chrishunt/update-favcount

Bump favcount.js to v1.5.0
FIX: Show "Begin Discussion" button when there are 0 replies
FIX: Show category text color in oneboxes
Adds unit tests for SearchController
Adds new QUnit assertion ("not") complementary to built-in "ok"
Don't seed a welcome topic on every db:migrate
FEATURE: add a 14 days window to consider topics new
Updated with tips for Postgres93.app

It took me a while to figure this out, so hopefully it helps someone use discourse in the future.
Update the OS X development documentation

* Remove some outdated information from the guide
* Add scripts/osx_dev to bootstrap a working development environment
* Add a Brewfile to track binary dependencies
Add site setting for category of topics created by embedding
copyediting on topnav tooltips