parsePackageInfo

Parses the actions in package-info.xml file from packages. - package should be an xmlArray with package-info as its base. - testing_only should be true if the package should not actually be applied. - method can be upgrade, install, or uninstall. Its default is install. - previous_version should be set to the previous installed version of this package, if any. - does not handle failure terribly well; testing first is always better.