Re-add `Metadata.for_package` platform version truncation

This inadvertently got deleted in 0bfc7aa12.
Remove `homepage` from Artifact publisher path

Since any Artifactory repo used for storing Omnibus packages already
requires a custom layout we can safely remove any Maven-isms in the
path.
Merge pull request #265 from opscode/schisamo/artifactory-homepage-global-config

Remove `homepage` from Artifactory path
Add support for Windows 8.1 Update (6.3.9600)
Add a `artifactory_base_path` global config option

Artifactory requires artifact paths to be prefixed by an organization 
(AKA orgPath in Artifactory speak).
Remove duplicate Config test converge in *_publisher_spec
Merge pull request #268 from opscode/schisamo/artifactory-base-repo-path

Add a `artifactory_base_path` global config option
Ensure parent directory exists in Builder#touch
Accept globbing patterns in Builder filesystem methods
Move windows_safe_path to Builder

This commit changes the way paths are represented in Omnibus. Prior to
this commit, paths would be operating-system-specific. However, with the
introduction of the new Builder DSL methods like +copy+ and +move+, Dir
globbing expects paths to be Rubyesque.

Now, all paths are represented using forward slashes (like the Unixes,
Darwins, and BSDs), and it is the responsibility of the software
writer to wrap command calls that shellout to the system in a call to
+windows_safe_path+.
Expand Project#install_dir relative to Config.project_root
Support pattern matching in Builder's filesystem methods
Bump to Ohai ~> 7.2
Add Builder#sync
Release v3.2.0
omnibus-ruby -> omnibus
Add support for overriding publish platform/version

This is useful in situations where packages that are build on one
platform/version are tested and released on 1..n other platforms/versions.

For example, one might build on Ubuntu 10.04 and test/publish on Ubuntu
11.04, 12.04 and Debian 7.
Expose platform/version override options on `omnibus publish` CLI
Add features for new CLI flags in publish subcommand
Merge pull request #272 from opscode/schisamo/publisher-override-release-platform

Add support for overriding publish platform/version