Added support for Server Account creation.

  - Added `Cloudpassage::Accounts.create`,
    `Cloudpassage::Accounts.reset`, and `Cloudpassage::Accounts.remove`.
  - Server commands can now be retrieved (`Cloudpassage::Server.command(id)`).
  - Fixed `token` bug while initializing `Cloudpassage::Server`
Merge pull request #1 from drewfradette/access-management

Added support for Server Account creation.