Add error handling to examples

The BitPay client library errors are emitted as events back to the
caller. If the caller does not receives and acts on them, the outcome
is a very uninformative message like this:

    TypeError: Uncaught, unspecified "error" event

To prevent this, show the error message to the caller, and hopefully
encourage better practice, this patch adds a very simple error handling
code to the examples where it would matter.

Signed-off-by: Gergely Imreh <imrehg@gmail.com>
added help text and line returns
Merge pull request #32 from braydonf/feature/helptext

added help text and line returns
Added feature to authenticate with email, password and two-factor code to approve a SIN, and added various prompts to commands.
command nomenclature
command nomenclature helptext
Merge pull request #31 from imrehg/errors

Add error handling to examples
moved BitPayUtils to lib/cli-utils.js and used hashPassword from libs
create account application example
Merge pull request #35 from bitpay/feature/createAccountExample

create account application example
Merge pull request #34 from braydonf/feature/register-sin-two-factor

Added feature to approve client identity with email, password and two-factor code with command ′keyapprove′
refactor all the things
update cli tool with rest client, scoped option to their proper commands, updated a couple examples
Merge pull request #36 from gordonwritescode/master

refactor all the things
added bitpay config command
fix new option scoped to login command
Merge pull request #40 from gordonwritescode/master

added bitpay config command
refactor login to use bitpay api token pairing code