Fixed: It cannot execute the "jake" commands correctly in the Cappuccino repository directory when it's not the Apple OS.

When running the "jake" commands in the repository directory, it would print:

$ jake --help
narwhal/packages/narwhal-jsc/bin/narwhal-jsc: line 33: narwhal/packages/narwhal-jsc/bin/narwhal-jscore: No such file or directory

Now, it will print:

$ pwd
/home/kevin/workspace/Cappuccino
$ jake --help
Usage: jake [OPTIONS] targets...
-f --jakefile FILE: Use FILE as the jakefile.
-T --tasks: Display the tasks with descriptions, then exit.
-D --describe: Describe the tasks then exit.
-P --prereqs: Display the tasks and dependencies, then exit.
	-v --verbose: Log message to standard output.
-h --help: displays usage information (final option)

Fixes #2181