Test access of data in vm guest

Specifically addresses test coverage of the virtual machine
guest data object. In particular the ability to retrieve the
macAddress attribute.

addresses https://github.com/vmware/pyvmomi/issues/20
test 'Iso8601' is properly deserializing dates.

Deliberately exercises the code in Iso8601 used by
VmomiSupport.py to validate that the import for
datetime reading is working as expected.

related to: https://github.com/vmware/pyvmomi/issues/112
python3: fix Iso8601 import statement

The import statement for Iso8601 was not properly
updated. This fix changes the import statement so
it works properly after python3 support changes.

fixes https://github.com/vmware/pyvmomi/issues/112
Merge pull request #117 from hartsock/issues/112

NameError: global name 'Iso8601' is not defined
Update test-requirements.txt - PyYAML

Down grade the PyYAML version for Fedora 20 support. Fedora ships with PyYAML == 3.10 see [PyYAML History](http://pyyaml.org/wiki/PyYAML) for version details.
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
tox support

initial tox support

closes: https://github.com/vmware/pyvmomi/issues/136
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
Merge pull request #137 from hartsock/tox

tox support
Merge pull request #118 from hartsock/issues/20

Test access of data in vm guest
Merge pull request #144 from vmware/v5.5.0-2014.bugfix

V5.5.0 2014.bugfix
Remove calls to atexit in tests

When using ``atexit.register(connect.Disconnect, si)`` in a test
the test framework process will create extra trace when it exits.
To avoid producing this trace, remove all calls to atexit in tests.

fixes: https://github.com/vmware/pyvmomi/issues/131
Merge pull request #146 from hartsock/issues/131

Remove calls to atexit in tests