* Use security find-certificate to look up Developer ID certificates for
  signing kernel extension and resulting installer package.

* Fix typo that caused the 2.6.0 installer package not being signed.
Build OS X 10.9 kernel extension with Xcode 5.0
Fix option parsing

Use the following options to specify a custom Developer ID for signing code and
installer package.

-j identity
   sign the code with the specified signing identity
-i identity
   sign the installer package with the specified signing identity