Prefer using `Utils.popen_read` for IO reads

See: https://github.com/Homebrew/homebrew/commit/625d891090c5d3f1ba5f9ca0a33e72d11dafa781
Extract sub-formulae to 'resources'

See: https://github.com/Homebrew/homebrew/issues/20212 for details
java-sdk7: 1.7.0_67 (jdk-7u67)
java-sdk: 1.8.0_20 (jdk-8u20)
Actually copy JCE Unlimited Strength policy files instead of soft-linking.
Soft-linked jars are not detected reliably at runtime.

Also, simplify resource installations.