2.0.2

Added

• Added check to ensure Shell extension is enabled before proceeding. Throws ShellException if it isn't enabled (Fixes #4).
• Added __toString() method and moved some code from display().

Changed

• Removed the login() method since original limitation introduced by Symphony::login() is gone.
• Simplified authentication prompt message.
• Ran php-cs-fixer over code base to ensure PSR2 compliant formatting.