making checksum comparison case insensitive
Merge pull request #374 from katiepru/fix_md5_case

making checksum comparison case insensitive
added latest releases includes CVE-2013-4073
use Homebrew openssl if available

Fixes #343, references #367
Merge pull request #376 from mislav/brew-openssl

use Homebrew openssl if available
ruby-build 20130628

Closes #375.
Debug versions