Factor out INI file parsing into util.
Create a vault for secret tokens and move some into it.

This is intended to reduce the number of critical secrets stored in the
INI file.  An initial subset of secrets is moved into the vault to test
things out.
Added missing netcat dependency

netcat is needed (tested on Ubuntu 12.04.3 LTS x86_64)
read_secrets: Don't transform INI options on output.
Remove unused util `interleave_lists`.
Factor activity fuzzing out of Subreddit.get_accounts_active.

This allows liveupdate to reuse the same code.
StripeController: handle case where description is None.
StripeController: fix typo in cancel_subscription.
GoldPaymentController: secret code must be unique.

create_claimed_gold attempts to create a row in the gold table and
will fail if secret is not unique.
Store stripe customer id in Account.gold_subscr_id.

We need to do lookups of Account by stripe customer id and
gold_subscr_id has an index. Previously was using a new attribute
stripe_customer_id which didn't have an index and lookups were too
slow.
StripeController: handle exception when customer isn't found.
StripeController: handle charge.failed with insufficient information.
ProfileBar: attribute is 'paypal_subscr_id'.
StripeController: don't cancel subscription if the charge was attempted.
Don't allow multiple gold subscriptions.
Gold: redirect to subscription page if use tries to resubscribe.
get_total_run: Fix handling for house campaigns.
PromoteReport: PromoCampaign end_date is not inclusive.
analytics: run on comments pages for promote links.
StripeController: don't raise exception for recent charges.