added cookbook to set env vars for passenger and unicorn or any app serv...

Description of your patch
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This cookbook will set env vars for any app control script that sources shared/config/env.custom 
A ruby wrapper script is also written out to shared/bin/ruby_wrapper
It sources the env.custom file and calls out to ruby.
If the stack is nginx_passenger* then /etc/nginx/stack.conf is updated to include a passenger_ruby configuration pointing at the ruby_wrapper script.

Estimated risk
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none, cookbooks are not enabled by default

Components involved
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ruby, nginx, passenger, unicorn

Description of testing done
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Booted up two test environments, one for passenger and one for unicorn and applied the new cookbook.  I modified my todo application to print out an environment variable in the application layout.  I deployed this app to both environments and ensured it was using the value of the environment variable I set in the cookbooks

QA Instructions
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Boot up unicorn and/or passenger environment.  Uncomment the require_recipe for the new cookbook, deploy an application that prints out an environment variable specified in the attributes, upload and apply cookbooks.  http://github.com/mdolian/todo will print out one of the ruby GC example variables in the application layout.