Add new module - OVFUtils

The bulk of this code is taken verbatim from RHEVMHelper.

It provides objects used to manipulate various bits of OVF/OVA
components in a reusable manner.
Refactor RHEVMHelper to use OVFUtils

All of the details surrounding OVF structure/generation/etc are now
available in OVFUtils, so consume that.
Add Vsphere support to OVFUtils
Add OVA plugin

This plugin takes an existing vsphere or rhevm target image, and
generates a new target image which is an OVA file valid for the
respective target.
Move OVFUtils.py from core imgfac to ovfcommon pseudo-plugin
Merge pull request #303 from jeckersb/ova_final

OVA generation support
Add license to plugins RPMS
Remove secondary code
RPM revision for Fedora

Simplify RPM version and release creation.  I have borrowed the
scheme used by Oz instead of our current technique based on git
describe.  The Oz scheme uses a time stamp which generally helps
avoid problems with version ordering.

Remove the mock plugins from the default RPM build.  They remain
in setup.py and can be built as RPMs by setting the %{build_mock}
macro, which remains the default behavior of the upstream
Makefile.  This avoids having the testing packages built when
using koji.
Merge pull request #304 from aeolusproject/feature/rpm_cleanup

RPM revision for Fedora
rpmlint fixes for plugin SPEC file
updates for 1.1.3 release
add python2 BuildRequires
change %define to %global in SPEC

This is to conform to Fedora package guidelines.
add an API version Provides and Requires

This approach should allow us to make future API changes behave in a
sane way with RPM.  For example, a future imagefactory release can
provide multiple versions of the internal API or eventually stop
providing the original 1.0 implementation.
Merge pull request #306 from aeolusproject/feature/plugin-api-take2

add an API version Provides and Requires
make subpackages own their top level directory
remove spurious unicode character from comments