adding support for submodules
Merge pull request #50 from narkisr/master

adding support for submodules in git source provider
Some whitespace cleanup.
Set default maintainer to "<user@hostname>".

Idea from @sepulworld in issue #51.
Add epoc= method to the Package base class.

Should fix #51.
Add changelog for 0.16.2.
Bump version to 0.16.1.

Changes:

* Add support for submodules in git provider. (narkisr / #50)
* Set a default maintainer.
* Fix problems with setting epoch. (#51)
build omnibus packages in tmp-dest

This is a breaking change! However, it improves consistency between
omnibus and regualar recipes. Regular recipes usually contain the
following:

    def build
      configure :prefix => prefix
      make
    end
    def install
      make 'DESTDIR' => destdir
    end

Omnibus recipes on the other hand looks like this:

    def build
      configure :prefix => destdir
      make
    end
    def install
      make
    end

With this patch, both can use the first form. Moreover building omnibus
packages without write privileges in /opt is now possible.

fixed the previous commit

added documentation
added a helper to package gems
added a ruby helper and fixed the omnibus examples