Compatible version numbers

Changes version standard to use `-` character when available.
By convention `-` is translated to `.` from now on when the
`-` character is prohibited by downstream systems.

Closes: https://github.com/vmware/pyvmomi/issues/127
Fix Open Source License classification

Sets the license field to a real pypi descriptor.

closes https://github.com/vmware/pyvmomi/issues/133
Fix README to be pypi legible

A pypi friendly version of the readme documentation.

closes: https://github.com/vmware/pyvmomi/issues/134
Improve sdist and bdist packaging

* Include tests in sdist
* Include license and notices in all distributions
* Update manifest
* Use more conventional file names for licenses, notices, etc.

related to https://github.com/vmware/pyvmomi/issues/133
related to https://github.com/vmware/pyvmomi/issues/123

closes: https://github.com/vmware/pyvmomi/issues/139
tox support

initial tox support

addresses: https://github.com/vmware/pyvmomi/issues/131
closes: https://github.com/vmware/pyvmomi/issues/136
following pypa example

Some minor packaging changes so that pyVmomi more closely
emulates the pypa package sample and tutorial as provided
by `The Python Packaging Authority` at https://github.com/pypa

closes: https://github.com/vmware/pyvmomi/issues/143
Merge pull request #135 from hartsock/release

Bug Fix Release