add packages
Add `APIClient`, which is used to interact with the Freckle API

* The `APIClient` class handles making calls to the Freckle API and
  parsing the responses, including handling pagination and setting the
  proper request paramters.
* Also creates special exceptions that explain what went wrong with an
  API call, and store the `errors` array for future use.
add skeleton of application, linking with APIClient and config file
add Rake task for making a "console" with an APIClient ready to use
ignore further changes to config.rb file
set ruby version to 2.1.2
Rename "PERSONAL_ACCESS_TOKENS" to "PAT"