Better tests for expected globals in scripts.

 On branch master
	modified:   test/commands/run_test.js
	modified:   test/fixtures/scripts/echo_args.coffee
Loads Application instance into scrip global space.

 On branch master
	modified:   lib/enginemill/command_factory.js
	modified:   test/commands/run_test.js
	modified:   test/fixtures/scripts/echo_args.coffee