capybara configurations
Library no longer supporting ruby 1.9.x

1.9.x will be deprecated in February of 2015, so there is little
incentive to write our new library to support it. 1.9.x users should
still be able to use V1 of the API.

This commit adds some changes, such as named arguments, that are
incompatible with 1.9.x.
Rakefile to clear added api keys

Local tests are run many times a day, but the Travis.CI tests are run
against test server accounts. So the default task (for Travis.CI) does
not clean up all API keys from the local server, but there is a rake
task that can be run locally or remotely to do this for you.
Add Rake tasks to clear limiters

When many integration tests are run in a short period, the local bitpay server
will refuse to create new keys due to the rate limiting function. This
rake task clears the ratelimiters database.
Bump required ruby version for gem

Ruby 2.0 does not support required keyword arguments, but we would like
to use required keyword arguments.
Use the public interface to retrieve an invoice

With this commit the following functionality is complete:
1. Using a token, pair a key
2. Create a new invoice
3. Retrieve the public invoice
Removing Compatibility methods

It doesn't make sense to be both cryptographically secure and insecure
in the same library.
Replace most ecdsa funtions with OpenSSL

This allows us to easily write a pem file to disk and recreate the key
from the pem file. We were unable to remove the ecdsa gem entirely, the
OpenSSL library does not handle EC signatures.
add license information
remove broken cli functions, update key_utils
add pair command to command line client

To support the pair command, cleaned up and extended client and
key_utils classes with more getters. Also added a param hash to the
invoice creation for extra items.

Updated Readme file