Add Inputs.io web client

Inputs.io is a web wallet that provides many features and security measures:

* Off chain transactions network
* On page payment buttons (https://inputs.io/button) - pay Bitcoin on another site, without leaving the page.
* IP based authorization - email sent when you sign in from new location
* Google Auth 2 factor
* GPG keysigning auth
* Automatic Tor/Proxies block if your account wasn't registered using anonymous proxies.
* Sending limits
* Free & automatic mixing
* Email notifications of payments sent and received
* Desktop notifications if supported by browser
* SSLLabs A+ score
* Pending audit page which provides cryptographic proof of no fractional reserve banking
* Responsive mobile version
* Bitcoin Foundation Silver Member

Inputs.io has transferred 82,000 BTC already, and quite a few sites support Inputs already.