contributing.md doc love

- link to download VirtualBox 4.3.20 needs to be updated
- fix/update broken image oh how to download binaries and extensions
- update reference to coderwall_v3
remove unused queues

- search_sync is staying around for now, because of how job uniqueness
is implemented
- seems like a good idea to also keep ‘default’ around even though no
worker/job uses it.  It is the default queue that sidekiq uses. So just
a smart move to keep it around?
- remove all other unused queues
Change route precedence of user_protips to come before slug_protips
Merge pull request #251 from codebender/contributing_love

contributing.md doc love
Merge pull request #254 from nicolasiensen/bounty/418

Quick fix the user protip route #418
Fixed error in the Octopussy badge
Reference user off team members
Merge pull request #252 from codebender/remove_old_sidekiq_queues

remove unused queues
Added placeholder for API
ActiveRecord & ruby optimizations

- select(:foo).map(:foo) -> pluck(:foo)
- select(:foo).collect(:foo) -> pluck(:foo)
- map { |foo| foo.bar } -> map(&:bar)
- map { … }.flatten -> flat_map { … }
- collect { … }.flatten -> flat_map { … }
- gsub() -> sub()
- gsub() -> tr()
Bounty 424 - Add design wip files
Merge pull request #255 from codebender/ar_ruby_optimization

ActiveRecord & ruby optimizations
Merge pull request #256 from tranhelen/design-wip

Bounty 424 - Add design WIP files
Moved design-wip out of app/assets
fix new relic team promo UI

- un-hide the promo copy
- show the entire promo t-shirt image
- align promo copy and image
- move call to action to the right side of the copy
Merge pull request #257 from codebender/fix/new_relic_promo_ui

fix New Relic team promo UI problems - Bounty #440
disable registration submit button after 1 click
Merge pull request #259 from codebender/stop_double_clicks_at_registration

disable registration submit button after 1 click
Fix User#on_team?
fix TeamsController#show