
The new stage() signature introduced by #66 breaks back-compatibility under Ruby 1.8.7. This fixes it by switching back to a one-argument block signature and using a new class to wrap both the Resource and Mktemp info for the staging context, in a signature-back-compatible way. Addresses homebrew/homebrew-core#529. Closes #135. Signed-off-by: Andrew Janke <andrew@apjanke.net>