Add descriptions of why the permissions are so extreme in chrome store description

[danfinlay]

This plugin requires about as scary-sounding permissions as a chrome extension can ask for, and that is almost definitely going to repulse some users.

What we can do to mitigate that effect is to document and be as transparent as possible about why we require those permissions.

The app store description is one place, I'm not sure if Chrome lets you explain on the permissions screen itself, but we should basically PR bomb why we require permissions as much as possible, so users are prepared for that authorization request.

[kumavis]

👍 yeah, need to identify the correct places to do this

[danfinlay]

Updated chrome store description to include this text:

Metamask is an extension for accessing Ethereum enabled distributed applications, or "Dapps" in your normal Chrome browser!

The extension injects the Ethereum web3 API into every website's javascript context, so that dapps can read from the blockchain.

MetaMask also lets the user create and manage their own identities, so when a Dapp wants to perform a transaction and write to the blockchain, the user gets a secure interface to review the transaction, before approving or rejecting it.

Because it adds functionality to the normal browser context, MetaMask requires the permission to read and write to any webpage. You can always "view the source" of MetaMask the way you do any Chrome extension, and we will be publishing our source code soon, to allow public auditing.