Cleanup README.md and s/couchdb.url/couchdb.host/

"URL" refers to a combination of protocol, hostname, port and path.
This option is actually just a hostname.
Fixed some typos, added screenshot to top of page.
Added animated image of baron
Fixing css issues for mobile view
Updated screen shots in readme. Applied fix to script reload for pay
 * Added latest screenshots to readme
 * Applied fix script that woul try to update the expiration time for
   BTC payments.
Fixed typo in readme. Removing unused error var
Fix startup failure with 0-conf mempool transaction

* updatePaymentWithTransaction() was lacking a callback when paymentChanged
  is false.  The missing callback was non-fatal for other users (jobs and
  walletnotify/blocknotify) so we didn't see the failure.
* The second parameter of listSinceBlock with bitcore does not seem to work as
  documented to limit the output to that number of confirmations.  Remove it.
* Clarify the comments in updatePayment a bit.
Fiat support requires non-default ENABLE_FIAT option

If enabled the bitstamped module saves BTC/USD price data once every
60 seconds.  This database can grow quickly so USD support is disabled
except for deployments who need it.

The bitstamped database can be safely wiped with a Baron restart if
there are no USD payments in progress.
Hide api_key from /invoices post error to reduce risk of leaking
Added documentation pertaining to ENABLE_FIAT to readme.
Removing unused variables from pay.js route
Removing unused variable from notify route
Added express middleware to catch 404 and other errors
 * All routes which baron does not support now return 404 upon request
Updated handling of 404 and other errors.
 * Baron now checks what type or respons the req accepts and responds
   appropriately when sending a 404
 * Setting status for catch all error block express middleware
Fiat must be always enabled in order to record the exchange rate
Fix for spot rate not updating for payments that arent watched
 * Fixes issue with spot rate not updating when a payment isnt watched
  (e.g. the user viewed the payment page and decides to pay a day later)
 * If a payment isn't being watched when we get the wallet notify. Baron
   now updates the payment using transaction.time as it is the best we
   can do in this situation.
 * closes #55
Test 7: updatePayment race with two payments to same address
Re-enable periodic lastBlockJob

Handles lost transactions due to cases like test7.
Will be handled cleaner by model v2.
Remove generatetoken.js
Add COPYING and MIT-style license in full to README.md