Merge pull request #93 from Ghost141/master

Fix jslint error in challenges.js
Fixed to check prize_id.
Active Billing Accounts API
recent design winning submissions
checkpoint api update
Merge pull request #94 from lsentkiewicz/master

checkpoint api update
Typo.
Handle no-rating, default to 0.
Fix.
Checking active.
disabled cache.
Fix.
continue the registration when rating and reliability is absent
Merge pull request #96 from wangzhihao/rating-absent

continue the registration when rating and reliability is absent
Validate Handle API
fix apiary for validate handle response
Merge pull request #97 from muzehyun/master

Validate Handle API
Update middleware.js to support unique cache key for private api.
Update middleware.js to support unique cache key for private api.
Merge remote-tracking branch 'origin/cache_fix' into cache_fix

Conflicts:
	initializers/middleware.js